Colour Management in C1 and Photoshop

[sandymc]

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You should not dismiss either Martin Evening or Bruce Fraser out of hand I think.

 

I don't - I don't know Martin Evening's work, but I do know Bruce Fraser's work - and he's probably better than most.

 

The problem is, and this covers most of the "experts" in the field, is they're totally out of date. The second edition of Bruce's book is 2004, the first edition was probably written in the 90's. What they lay out is a bunch of "what worked for me" type solutions. Which probably did work back then as hacks to make what were basically disfunctional color management environments work. But when they wrote this stuff, they never distinguished between what were hacks, and what is actually sound theory that the reader can still rely on. So you get lots of people reading this stuff, and taking it all, including the hacks, as gospel.

 

Which is really difficult for those of us that write imaging software, because we keep on getting variations of "the color is wrong" questions, based on hacks from 5 years ago that (a) are no longer required and ( are often totally counter-productive.

 

So this is an issue for me....

 

Sandy

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[ptarmigan]

I don't - I don't know Martin Evening's work, but I do know Bruce Fraser's work - and he's probably better than most.

 

The problem is, and this covers most of the "experts" in the field, is they're totally out of date. The second edition of Bruce's book is 2004, the first edition was probably written in the 90's. What they lay out is a bunch of "what worked for me" type solutions. Which probably did work back then as hacks to make what were basically disfunctional color management environments work. But when they wrote this stuff, they never distinguished between what were hacks, and what is actually sound theory that the reader can still rely on. So you get lots of people reading this stuff, and taking it all, including the hacks, as gospel.

 

Which is really difficult for those of us that write imaging software, because we keep on getting variations of "the color is wrong" questions, based on hacks from 5 years ago that (a) are no longer required and ( are often totally counter-productive.

 

So this is an issue for me....

 

Sandy

 

I'm sure you are right but as a photographer and photo imaging 'software user' (oh I also work for a software company for my real job) I want to spend most time shooting images not playing with imaging software (sorry ) and as typically (with PS CSx in particular) there are 3,4 or 5 ways of achieving most 'end results' and I don't have the time or inclination to spend trying to figure them out for myself. I'd much rather have Martin or Bruce tell me. I can then experiment around for myself.

 

The book in question from Evening is a 2007 edition for CS3 which I would by now have replaced had I updated to CS4 which I at present have decided not to do.

[Guest WPalank]

Okay, this is the comparison.

 

The TIFF File on the left hand side is converted from DNG to 16 bit TIFF by using C1, and re-opened here in CS3. Its colours show the same as the original DNG as displayed in C1. Colour space is aRGB.

 

The JPG File on the right is the conversion from the TIFF, exactly followed jaapv's procedures as stated above.

 

Then I re-opened the JPG, compared with the TIFF. You can tell the differences in colours by comparing the blue.

 

I just don't understand why this happens.

 

I can't find where you have explained how you get from the 8 bit sRGB TIFF file to a Jpeg.

 

So I have to assume you are going File>Save As.... (how to get there on a Mac anyway).

 

In the dialogue box that comes up, make sure "Embed Color Profile" is selected:

 

 

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Otherwise, it will revert back to the original color profile. (I mistakingly have TIFF in the "Format:" drop-down menu. It should read JPEG obviously.)

[Jamie Roberts]

I'm sure you are right but as a photographer and photo imaging 'software user' (oh I also work for a software company for my real job) I want to spend most time shooting images not playing with imaging software (sorry ) and as typically (with PS CSx in particular) there are 3,4 or 5 ways of achieving most 'end results' and I don't have the time or inclination to spend trying to figure them out for myself. I'd much rather have Martin or Bruce tell me. I can then experiment around for myself.

 

The book in question from Evening is a 2007 edition for CS3 which I would by now have replaced had I updated to CS4 which I at present have decided not to do.

 

The problem here, however, is that Sandy is right and Evening is wrong on this So if you're going to experiment for yourself, trust those of us who have been down the path before and start off in the right ballpark (sorry for the mixed metaphor).

 

What doesn't get addressed in Evening's book (which I've had for awhile) is that people really don't understand how printing works.

 

So yes, it's true that sRGB is clipped a little bit in Cyan (and yellow) for CMYK (and that would be SWOP 2 coated CMYK, not some other CMYK or CCMMYKK as used in some Epsons)

 

However, there are very few CMYK presses that achieve cyan at 100% saturation anyway, cyan being a notoriously difficult colour to print, actually

 

So in that case, ColorMatch or sRGB to CMYK ensures that there is an easy transition from a working space (sRGB) to the printing space (CMYK). In other words, if you want your images to look the way you proof them, sRGB is a better practical space for CMYK!! Evening's advice is exactly opposite of what you should do if you want to keep things simple.

 

On the other hand, there isn't a printer on earth that can print the gamut of ProPhoto--though transparencies are a different kettle of fish... for the most part though, are you going to be making Ektachrome slides of your files?

 

Anyway, when you transform colours from a space like ProPhoto to a (much narrower) print space, you have to make all kinds of assumptions about how different colours should print. As it turns out, if you have a wide gamut image (and not very many are really all that wide) you sometimes get terrible colour shifts going from ProPhoto to the comparatively small print space.

 

So you actually need to understand what you're trying to achieve in print first; then you pick the profile you need to keep, for example, primary colours from shifting to much in the conversion process.

 

If you want to see how this works, check out the gamut viewer at Dry Creek Photo, here:

 

Interactive Color Space Gamut Models

 

I know this sounds hard (and in the finer parts it is) and so the amateur advice is always "use aRGB" which is at least big enough so that you're not clipping anything out of your cameras directly (but of course you're never clipping if the colour information isn't there to begin with!).

 

And FWIW, the "experts" you quoted disagree anyway (Bruce Fraser would have never recommended ProPhoto for precisely the reasons I mentioned; I believe his preferred "hack" space was "BruceRGB"...

 

So once again, if you're serious about maintaining excellent colour AND the ability to transform to various print spaces, then I'd recommend spending the money on Joseph Holmes's D profiles:

 

Joseph Holmes - RGB Working Space Profiles

 

They're the ones I use for archiving, and they are great. Or just use aRGB and be careful to convert to something smaller when you need to for printing.

[bono0272]

I can't find where you have explained how you get from the 8 bit sRGB TIFF file to a Jpeg.

 

So I have to assume you are going File>Save As.... (how to get there on a Mac anyway).

 

In the dialogue box that comes up, make sure "Embed Color Profile" is selected:

 

 

[ATTACH]150997[/ATTACH]

 

Otherwise, it will revert back to the original color profile. (I mistakingly have TIFF in the "Format:" drop-down menu. It should read JPEG obviously.)

 

Yes I use: "File>Save As" to make the 8-bit sRGB TIFF to JPG. And I also select the "Embed Color Profile" as well.

 

One question is: as per jaapv's advices I converted the aRGB TIFF to sRGB for web posting, then saved it as JPG. So while I am using "Save As", should the "Embed Color Profile" be aRGB or sRGB for the JPG file?

 

Another question is: I calibrate my monitor by using an Eye One, and it creates a monitor icc profile. I can find inside - Control Panel>Display>Settings>Advanced>Color Management, the computer is default using the most update monitor icc profile. Is this correct?

 

Thanks a lot for answering my tons of questions.

[Jamie Roberts]

{snipped}

 

One question is: as per jaapv's advices I converted the aRGB TIFF to sRGB for web posting, then saved it as JPG. So while I am using "Save As", should the "Embed Color Profile" be aRGB or sRGB for the JPG file?

 

Another question is: I calibrate my monitor by using an Eye One, and it creates a monitor icc profile. I can find inside - Control Panel>Display>Settings>Advanced>Color Management, the computer is default using the most update monitor icc profile. Is this correct?

 

Thanks a lot for answering my tons of questions.

 

If you've successfully converted from aRGB to sRGB, then when you save the file the "Embed Color Profile" should read sRGB. If it doesn't, you still need to convert.

 

You don't *need* to embed the profile for the Web though, unless you're sure that the person looking at the file has a color-management-enabled browser. But you still want to make the conversion to sRGB, because even if the browser isn't colour managed (like Internet Explorer) sRGB will be close.

 

In PS CS4 if you use "Save for Web..." there is a checkbox that lets you convert to sRGB when you output the JPEG, which is handy.

 

And yes, your monitor should use the most recent profile you create with EyeOne Match.

[bono0272]

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Thanks Jamie, I will try again tonight.

[bono0272]

Dear Jamie amd Jaapv,

 

Finally I have both the TIFF and JPG files' colours matching with each other while opening both in CS3 the same time and compare. Thank you very much for the patient guidance.

 

However, the JPG (and the TIFF also) looks again with higher saturation if just simply viewing it by using "Windows Picture Viewer". Also when I post the JPG to web page it shows a higher colour saturation than the original photo appears in CS3.

 

Why is this happening?

[Jamie Roberts]

{snipped}

However, the JPG (and the TIFF also) looks again with higher saturation if just simply viewing it by using "Windows Picture Viewer". Also when I post the JPG to web page it shows a higher colour saturation than the original photo appears in CS3.

 

Why is this happening?

 

Neither Windows Picture Viewer nor Internet Explorer have colour management, so it is ignoring the sRGB profile and you're just seeing an unadjusted image.

 

Remember, that's also the way anyone with Internet Explorer or Firefox will also see your files (though FireFox is getting there with colour management--it's still pretty buggy IMO).

 

This is one reason why it's so hard to tell anything about colour over the Web unless you're measuring it--not looking at it

[bono0272]

Seems that I have to accept the truth......