MobiWorkshop MW2 White Balance

FundyBrian said:
Can you show an example of how you use this? I’m thinking it is something that would be helpful for people to see.

Another app that interests me is MaxCurve. I use curves all the time in Photoshop but in a way the corrections in InstaFlash Pro, or AC/DC Pro are easier to use. However, MaxCurve does something different in that you have access to all the curve types at once, RGB, CMYK, LAB, HSL, Lightness. In Photoshop, when you are editing an RGB image you only have the RGB curves available to you.
But if you think about it, with RGB & CMY curves at the same time you have direct access to all 3 planes of the colour wheel and whatever direction you want to work.
Also, if you try some of the presets in MaxCurve and look at all the curves you can see how that preset is made. Some of them are quite inciteful to examine.
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Would you be able to do an overview of curves? I've never really understood them either.
 
RoseCat said:
The color thing is a bit wonky to me as I come from a painterly background and know the primary colors as red, blue, yellow.

Inkjet printers use magenta, cyan, yellow (which makes more sense to me as magenta and cyan are types of red and blue).

But red, blue, green feels sort of :alien:.
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I'm sooo with you! Alone in photoshop on a desktop I feel pretty comfortable to do things with cmyk. But I'm helpless when the image is rgb. Unfortunately most filters and stuff work only there. But for print you need CMYK. Then you have a perfect RGB image and turn it into CMYK and you have rubbish. Horrible, but happens. :(
 
FundyBrian said:
Auto White Balance

Digital cameras have White Balance to adjust the colour to suit any given lighting condition. Auto White Balance, or AWB as it is usually marked in the camera, attempts to automatically adjust the balance of colour in our photos to suit the prevailing light conditions. Overall, it works fairly well with average subjects. Here the word “average” takes on a specific photographic meaning. It works about as well as auto-exposure - and you know how well that works (eye roll). The scenes it works OK on I think of as the Grey World. Even mix of colours, average reflectance, ordinary lighting.

Different approaches to white balance.

I have the impression that some people think that paying attention to white balance at the time of photographing is more than they want to think about and would prefer to deal with the problems later. That means spending lots of time in editing fiddling with the sliders to adjust the colour so they think it looks pleasing. They may have to start by overcoming a considerable colour shift and they probably can’t tell when the colour is anything like the way they saw it. If you have to make big changes to colour in regular jpeg images you stand the risk of introducing more colour noise.

If you understand how Auto White Balance works you can still work the same way except you will have a much better idea of how to get the colour you want.

The other approach is to get the colour right at the time of photographing and save all the time you would have spent editing the colour later to get it right. Of course you still have the option to exercise your creative expression but now you have a known starting point.

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This is how the scene looked - bright warm red wall, yellow chairs.

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Auto White Balance really did a number on this image. But you can see why. It would take one look at this scene and say “Where’s the blue/cyan?” The result is so predictable that you should be alerted to take steps to circumvent the problem before pressing the shutter.
I don’t usually save any off colour results but this case was so extreme it was too good to pass up.

Auto White Balance changes the white balance in every picture based on the balance of colours reflected from the scene. In other words the white balance is dependent on the colour of the subject while it really should be dependent on light conditions - except it has nothing reliable to read from.

Let’s say, you’re taking pictures at a parade on a sunny day and a yellow car goes by. The Auto WB thinks “too much yellow” so it adds blue. A red car goes by and it thinks “too much red” and so on with each colour that goes by. Unless a neutral grey car comes along none of the cars gets the correct colour and the background colour in every picture is different. Does that make any sense? Even worse, during editing you have to adjust every single picture, and each once will be different even though the light conditions were the same.

Instead, you’re going to do just one thing. Go to the white balance menu and select the sunny day setting. That’s it! Now the colour balance will the same in every picture, as it should be, and each car will have the proper colour and you won’t have to edit the colour in any of the photos. Just that one thing saved you lots of fiddling.
If it is a cloudy day instead you simply select the cloudy day icon. OR- make a custom WB reading from a known neutral subject, such as a white balance card, or an 18% grey card that also claims to be good for white balance (not all are). And now you once again have a correct white balance setting.

Here you thought it was going to be a lot of extra fiddling around when in fact it is just one thing and it saves you maybe dozens of individual adjustments.

What does correct colour balance look like?

If we look at the fine art definition of white balance it would say something about the colours being true or looking the way they are supposed to look. But colours can vary quite a bit and who is to know. You find your main clues by looking at the neutral tones in the image, in particular, the whites and blacks. If your whites are white and your blacks are black who can quibble about the colours in between?

Methods for getting the correct colour at the time of Photographing.
  • Evaluate your scene to see if everything looks normal and if so then AWB will probably work fine.
  • If your evaluation reveals an unusually large area of one colour that will throw off the white balance then you need to take steps to prevent that. Instead of relying on reading the light reflected from the subject pick a method that reads the light itself.
  • A - Select a white balance preset. Many camera apps have provision to use white balance presets. Just like a regular camera, there is a menu with a set of standard white balance presets. Sun, overcast, shade, indoor 3200ºK, flash, etc. You simply select the one matching your lighting conditions and carry on.
  • B - Making a custom white balance reading. If your lighting conditions don’t match any presets you have the option to measure the colour of the light where you are now and save it as a custom white balance. You need a known neutral surface to read from, such as a white balance card made for the purpose. You can also use any truly neutral card such as a piece of white photo mount board. In a pinch some white paper will do but bear in mind that it is actually quite hard to find truly white paper. The problem with this best option is that not very many apps have provision for making a custom white balance.

Another way to think of auto white balance (AWB):

You have a red flower on a green bush. The AWB looks at the scene and says “where’s the blue?”, and it puts some in until it finds a balance - the wrong balance. This is why, in this situation, that your red flower ends up with a bluish colour shift. And this same colour inaccuracy is happening in practically every blankety blank shot where the colours in the subject don’t happen to average out neatly, and it’s very aggravating!!#*! So I would propose that Auto White Balance be dubbed Aggravating White Balance instead.

PureShot is my manual camera of choice and one reason is the easy access to the white balance lock. It’s right on the main camera screen, not buried in a menu. In any unknown light condition the fastest method to get the WB correct is to take a reading off a known surface, such as a WB card. You just hold the card in front of the camera picking up the light at the same direction you are photographing and tap the WB lock button. You may have to angle the card slightly to avoid a shadow but generally tipping the card slightly to catch the light at the same angle it is falling on the subject works best. That’s it, you’re all set. No guessing. No experimenting with different scene settings or °K scales. Bullet proof. Make sure you aren’t wearing wildly coloured clothing, like a yellow raincoat, because the light reflecting from the coat will pollute the white balance reading.

What about creative expression?

If you submit photos to a high end competition with trained judges they might take a dim view of your personal expression if your blacks have a reddish tinge or your whites are bluish. Certainly there is room for creative expression but it should be done well.
The problem is that careless use of white balance sliders can shift all the colours in the picture including the whites and blacks
It is entirely possible to adjust colours in a certain direction without messing up the whites and blacks - using curves.


Methods of correcting colour shifts during editing.

Some editing apps have a white balance eyedropper tool. The idea behind this is you sample a neutral grey area within your image and the app adjusts the colour to provide a true neutral grey. I have found that my pictures hardly ever have any real neutral grey tone in them to sample from. I might select the bark of a tree that I think is probably neutral grey so I sample there and, whoa!, the colour goes off wildly in some unpleasant direction. Nope, I guess that wasn’t a neutral tone. The only time I find that sort of tone to read from is when I put a grey card in my image for test purposes.


A Dilemma:

Here’s a situation I want you to see and maybe you can find a way around it.
Let’s suppose we have a picture that has shifted towards magenta and we want to bring it back to normal. The typical white balance slider is blue to yellow. Sometimes another slider is present, called tint, going from green to red.

Have a look at the colour wheel to see where those two sliders operate.

View attachment 119530

The black arrows represent the two sliders we usually have and the magenta colour shift requires a lot of experimental juggling to try to get to the amount of green correction we need. Better if we had 3 sliders. Yellow-blue, Red-cyan, magenta-green. Better yet if we had a joystick control that could go in any direction needed. In a graphical interface we could simply have the circle and drag your finger in whatever direction is needed, even those in between areas. Much more intuitive.

Here’s Your Workshop Assignment:
  • find a couple of pictures from your files that show white balance problems and try to explain why that happened.
  • Try pointing your camera at some solid colour areas and see what the AWB does to the colour.
  • What is likely to happen to skin tones photographed in the baby’s room that has pink walls?
  • What is the likely colour shift that will occur when photographing greenery?
View attachment 119533



Next I will post a list of some cameras apps that have white balance controls.
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Sorry, Brian, I missed that. Thought it's another 2weeks challenge. Hope I still get an answer but first read my way through. :)
 
GroovyGouvy said:
I'm sooo with you! Alone in photoshop on a desktop I feel pretty comfortable to do things with cmyk. But I'm helpless when the image is rgb. Unfortunately most filters and stuff work only there. But for print you need CMYK. Then you have a perfect RGB image and turn it into CMYK and you have rubbish. Horrible, but happens. :(
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This is interesting to me. Working in CMKY is so much more limited in Photoshop than RGB. There are many things that do not work in CMYK mode. A key difference is that the curves are sort of reversed.

Sometimes converting an RGB image to CMYK takes some fiddling to get a good result. You have to remember that CMYK has a smaller gamut so there are colours visible in RGB that cannot exist in CMYK. You need to work with the rogue colours to pull them back inside the acceptable range. I have seen many cases where no visible changes happen when converting RGB to CMYK.
 
FundyBrian said:
This is interesting to me. Working in CMKY is so much more limited in Photoshop than RGB. There are many things that do not work in CMYK mode. A key difference is that the curves are sort of reversed.

Sometimes converting an RGB image to CMYK takes some fiddling to get a good result. You have to remember that CMYK has a smaller gamut so there are colours visible in RGB that cannot exist in CMYK. You need to work with the rogue colours to pull them back inside the acceptable range. I have seen many cases where no visible changes happen when converting RGB to CMYK.
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True, sometimes you don’t see the difference, but sometime there are canyons between it. And to me the reversed curves are the RGB ones in my eyes. :D And yes, that’s what I say, you can do much more in RGB in photoshop as CMYK. Nevertheless I do need CMYK for print. :) so there is no way round. :)
 
GroovyGouvy said:
True, sometimes you don’t see the difference, but sometime there are canyons between it. And to me the reversed curves are the RGB ones in my eyes. :D And yes, that’s what I say, you can do much more in RGB in photoshop as CMYK. Nevertheless I do need CMYK for print. :) so there is no way round. :)
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The losses in CMYK will be most noticeable in the bright yellow-greens, purples and oranges. An RGB photo that is hot in those colours will suffer the greatest losses. Perhaps greater success will be found in focusing on the areas where CMY is strong rather than where it is weak.

You have become used to working with only the subtractive primaries. That is only half of the story. That is like looking at the RGB-CMY colour wheel and seeing only CMY. The other half is the additive primaries. Every picture starts out as RGB.

Here’s a suggestion. When your final result will be in CMYK, in Photoshop set your viewing setting to show the CMYK preview, even when you are working in RGB. Also turn on gamut warning so that when you are editing an RGB photo before converting it to CMYK it will show you when your RGB is getting too pumped up to exist in the CMYK colour space. I’m not at my computer at the moment, but when I am there I will check the steps to do this with the proper names of the selections to make.
 
FundyBrian said:
The losses in CMYK will be most noticeable in the bright yellow-greens, purples and oranges. An RGB photo that is hot in those colours will suffer the greatest losses. Perhaps greater success will be found in focusing on the areas where CMY is strong rather than where it is weak.

You have become used to working with only the subtractive primaries. That is only half of the story. That is like looking at the RGB-CMY colour wheel and seeing only CMY. The other half is the additive primaries. Every picture starts out as RGB.

Here’s a suggestion. When your final result will be in CMYK, in Photoshop set your viewing setting to show the CMYK preview, even when you are working in RGB. Also turn on gamut warning so that when you are editing an RGB photo before converting it to CMYK it will show you when your RGB is getting too pumped up to exist in the CMYK colour space. I’m not at my computer at the moment, but when I am there I will check the steps to do this with the proper names of the selections to make.
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In Photoshop, first you go to the View menu, and down to the first item Proof Setup. (You will probably need to have a picture open on your screen in order to make all the selection choices active)
In that pop-up menu you select Working CMYK, which presumably you have already set in your Adobe suite-wide colour settings. That way your colour settings are consistent between Photoshop, InDesign, Illustrator, and whatever other Adobe programs you use.

For me, the CMYK setting is US Web Coated (SWOP) v2. This setting depends on the type of printing the press does considering the type of paper being used. If you don’t know the print shop can tell you.

Once you have that set, go back to the View menu and select the second item - Proof Colors and a check mark will appear beside it on the list to show it is on.

Then, back to the View menu and select the 3rd item on the list - Gamut Warning. A check mark will appear beside the name when it is turned on. If your RGB image has any colours that are outside of what can be printed by CMYK they will show as greyed-out areas

Now when you look at your RGB image you will be seeing it in terms of how it will be rendered in CMYK so when you make the CMYK conversion you won’t have any surprises. Even before you RGB image has been converted you will see how it will turn out. If you see any problems you can fix them before conversion.

In the CMYK conversion there is the option to clip the out-of-gamut colours (which isn’t very nice) or Photoshop can progressively squeeze the problem colours into the acceptable range.

When you are not working towards a final CMYK product it might be better you go back to the standard RGB settings. If making RGB images for on-line use pick the Internet Standard RGB (sRGB) or if you are working with images headed for your image bank and you want to keep the full colour width, then picking Monitor RGB is probably best, especially if you have a calibrated graphics monitor.
 
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FundyBrian said:
Then, back to the View menu and select the 3rd item on the list - Gamut Warning. A check mark will appear beside the name when it is turned on. If your RGB image has any colours that are outside of what can be printed by CMYK they will show as greyed-out areas
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I've been printing quite a few digital images lately, and I'd like to add one note about the Gamut Warning. It grays out all colors that are beyond the printable gamut of your current paper/printer settings, but it gives no indication of how far out of gamut those colors are. So colors that are just a bit beyond the gamut will be grayed out just like colors that are way beyond. The first few times you turn on Gamut Warning, it can be rather a shock to see large sections of your image disappear into blank gray, but don't despair -- the situation usually isn't as bad as it looks. Just take a few deep breaths, begin your adjustments, and watch your image start to reappear.

Also, if you print an image that has out of gamut colors, the out of gamut areas will still print, but with the closest in-gamut colors your printer/software can manage. Sometimes this works out OK; sometimes it turns a lively image flat and dead.
 
terse said:
I've been printing quite a few digital images lately, and I'd like to add one note about the Gamut Warning. It grays out all colors that are beyond the printable gamut of your current paper/printer settings, but it gives no indication of how far out of gamut those colors are. So colors that are just a bit beyond the gamut will be grayed out just like colors that are way beyond. The first few times you turn on Gamut Warning, it can be rather a shock to see large sections of your image disappear into blank gray, but don't despair -- the situation usually isn't as bad as it looks. Just take a few deep breaths, begin your adjustments, and watch your image start to reappear.

Also, if you print an image that has out of gamut colors, the out of gamut areas will still print, but with the closest in-gamut colors your printer/software can manage. Sometimes this works out OK; sometimes it turns a lively image flat and dead.
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While I was checking on the settings & steps above I opened a picture from my desktop that I was sure would be off the charts for CMYK but I was surprised to see only one small area showing the gamut warning, and that area had the sun in the picture. So not the colour but extreme exposure white-out.
 
GroovyGouvy said:
But for print you need CMYK. :(
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Here's an other thing I've never really understood. My digital design background is mainly web design so print was rarely an issue. I've since started doing design for print and just carried on in my own little RGB world with the same tools as before without a problem.
So why CMYK for print?
 
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rizole said:
Here's an other thing I've never really understood. My digital design background is mainly web design so print was rarely an issue. I've since started doing design for print and just carried on in my own little RGB world with the same tools as before without a problem.
So why CMYK for print?
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Answering my own question......
As has been noted above, RGB is additive, so adding one colour to another produces a brighter colour. But printers are subtractive - add one colour to another makes a darker colour so printers start with lighter colours and add them together to make darker ones.
Apparently printers convert RGB's on the fly to CMYK so I guess you want CMYK for printing so you know you'll get exactly what you want, not the printer's conversion.
 
rizole said:
Answering my own question......
As has been noted above, RGB is additive, so adding one colour to another produces a brighter colour. But printers are subtractive - add one colour to another makes a darker colour so printers start with lighter colours and add them together to make darker ones.
Apparently printers convert RGB's on the fly to CMYK so I guess you want CMYK for printing so you know you'll get exactly what you want, not the printer's conversion.
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Yes, printing from RGB works perfectly well, most of the time. Using the CMYK preview helps to see how it will turn out in advance. Making special printer files by converting RGB to CMYK before printing isn’t really necessary for home printing. For one thing, if you decide to print on a different paper your carefully made CMYK conversion will no longer be correct. If your file is CMYK the printer won’t correct for the change. So there is some advantage in allowing the printer to do the CMYK conversion based on the paper type, etc.

When making your CMYK conversion it needs to be made to suit the end use - the printer, based on paper type, ink set, etc., rather than a generic or general purpose CMYK profile. I would bet the printer knows the conversion better than Photoshop. If you have a pro printer and have the paper type profiles downloaded to your system they should appear in Photoshop during the CMYK conversion so you could select the correct printer/paper profile for your application. Incidentally, for some printers there are the standard consumer grade profiles and Pro profiles you can download if you want. The pro profiles are substantially larger in memory use so I expect there is more going on there.

This works as long as you are using a paper for which your printer has a profile for. My Epson printer only has profiles for Epson papers.

I always find it takes a few tries to arrive at the best print result (via test patches). I don’t want to be re-editing the photo every time so I use adjustment layers. With adjustment layers I can revisit changes without ever altering my original image. I could add 2 or 3 different adjustment types, such as contrast, colour balance, saturation, and be able to readjust them whenever I wanted and only when happy make the final file. I even found it was better not to make a final file because when I change printers everything can slightly change. So in the long run it is better to have a printer curve to suite my printer and when I change printers just changing the printer curve will get me up to speed the fastest way.
 
rizole said:
Here's an other thing I've never really understood. My digital design background is mainly web design so print was rarely an issue. I've since started doing design for print and just carried on in my own little RGB world with the same tools as before without a problem.
So why CMYK for print?
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There's a explanation here https://www.printplace.com/blog/reasons-for-cmyk-printing/ for anyone who's interested (since rizole's answered his own question).

What I learned, way back when, was that you used CMYK only for work that was going to be printed on an actual printing press by a commercial printer. But here's an argument from David Blatner that these days it's better to stick to RGB in most cases: https://indesignsecrets.com/import-rgb-images-indesign-convert-cmyk-export.php
 
terse said:
There's a explanation here https://www.printplace.com/blog/reasons-for-cmyk-printing/ for anyone who's interested (since rizole's answered his own question).

What I learned, way back when, was that you used CMYK only for work that was going to be printed on an actual printing press by a commercial printer. But here's an argument from David Blatner that these days it's better to stick to RGB in most cases: https://indesignsecrets.com/import-rgb-images-indesign-convert-cmyk-export.php
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Thanks for the references. Very handy.
For commercial work it is always best to follow the instructions from the printers so your file will match their processes. So far in my area the printers are still asking for CMYK output.

Another thing. When printing to your own printer you can select the specific printer profile in your proof setup.
 
FundyBrian said:
For commercial work it is always best to follow the instructions from the printers so your file will match their processes.
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Exactly, not only for the color space but also for the ICC profile if the printer provides/specifies one (and they should).

And while poking into this topic on the web, I had a D'oh! moment when someone pointed out that most modern inkjet printers beyond the basic models use more inks than just CMYK. My Canon Pro-10, for example, uses 9 inks (plus a gloss optimizer), adding Photo Cyan, Photo Magenta, Red, and Gray to the mix, and having Photo Black and Matte Black in place of the single K. Some Epson printers added orange and green in place of the Canon's red.

In other words, the inkjet printer is doing some internal conversions to employ all these inks, regardless of whether you send RGB or CMYK. There's no escaping it.

In printing digital images (especially non-photographic ones -- think zenjenny or ImageArt or Starzee -- on inkjet printers, I've found the most difficult problem is that so much of the color may lay outside the range of colors the printer can reproduce. So the challenge becomes adjusting the image so that all colors are printable while maintaining the look of the original. It'll drive you crazy, not to mention using up a lot of ink and paper.
 
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I may be the only person annoyed by this, but why wouldn’t they have used B for Black instead of K for blacK. All the other colors use the first initial. ANNOYING. :feet:
 
terse said:
Exactly, not only for the color space but also for the ICC profile if the printer provides/specifies one (and they should).

And while poking into this topic on the web, I had a D'oh! moment when someone pointed out that most modern inkjet printers beyond the basic models use more inks than just CMYK. My Canon Pro-10, for example, uses 9 inks (plus a gloss optimizer), adding Photo Cyan, Photo Magenta, Red, and Gray to the mix, and having Photo Black and Matte Black in place of the single K. Some Epson printers added orange and green in place of the Canon's red.

In other words, the inkjet printer is doing some internal conversions to employ all these inks, regardless of whether you send RGB or CMYK. There's no escaping it.

In printing digital images (especially non-photographic ones -- think zenjenny or ImageArt or Starzee -- on inkjet printers, I've found the most difficult problem is that so much of the color may lay outside the range of colors the printer can reproduce. So the challenge becomes adjusting the image so that all colors are printable while maintaining the look of the original. It'll drive you crazy, not to mention using up a lot of ink and paper.
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More good points. I have a 9 ink Epson printer. I think part of the theory behind the extra inks is that it is easier to match certain colours. For instance, mixing a very tiny amount of a dark ink when the resulting tone is light, is much easier using one of the light-toned cyan, and magenta inks. The use of 3 blacks greatly improves tonality for B&W photos. But at $100 a pop for each of those cartridges it gets a bit pricy. It is certainly a lot better than my first printers years ago. But probably not as good as the next printers coming along soon. It’s too bad the inks wouldn’t all run out at the same time as that would make switching to a new printer a lot easier. Otherwise you are thinking about the $300 or $400 of ink still sitting in the printer if only you just bought a couple of new cartridges.
One thing for sure, my next printer will have roll printing. I had that on my previous printer and printed several panoramas up to about 5’ long. When I bought my new printer I foolishly presumed it would have all the same features as my old one, except bigger. Major bummer. I was so focused on the wide printing and all those inks in bigger cartridges...
 
RoseCat said:
I may be the only person annoyed by this, but why wouldn’t they have used B for Black instead of K for blacK. All the other colors use the first initial. ANNOYING. :feet:
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I always wondered about that, too. :D And I read a day or two ago that K actually stands for Key, and the Key color happens to be black.
 
RoseCat said:
I may be the only person annoyed by this, but why wouldn’t they have used B for Black instead of K for blacK. All the other colors use the first initial. ANNOYING. :feet:
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Because B is already used for Blue. RGB-CMY. Black doesn’t appear on the colour wheel. Black was primarily added to allow printing text as a single solid ink colour rather that having to keep the 3 CMY layers so precisely in register. That makes for much cleaner text. It is just a commercial printing standard going way back. Maybe they just enjoy confounding customers.
If you want to print text in red on a poster the red will be made up out of magenta & yellow layers in register. If you pay extra you can use special spot colours when the specific colour match is essential - such as for commercial logos. On the other hand, If you realize Red will be printed as two colour mixed together and you want the clarity of a single colour you could pick magenta or cyan instead.
 
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