Help me understand color space...

[hahn73]

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I'm having trouble with C1 LE in that using Jamie's excellent chrome color profile, and I suspect it's because I'm failing to fully understand color spaces. So first, I get the picture to look the way I want on screen. I have the "destination" color profile set to Adobe RGB. Then when I process the photo with the settings at "jpg, high quality" and "convert to destination", the photo ends up looking de-saturated when I view the jpg. And so I end up having to oversaturate the DNG file in C1 in order to get a jpg that looks the way I want, but then I'm guessing at the final pic and often I end up doing the processing 6-7 times before getting it right. This happens even when I choose sRGB as my destination color space. What am I doing wrong??

[george +]

This may not be the perfect answer. But I have found that setting the output to 16 bit TIFF; then processing it in PS and finally converting it to JPG (and eliminating the 60MB temporary files) produces consistently better quality images.

 

This was not my discovery, there was a discussion on this before on the Forum.

 

If anybody has a way to eliminate the step with the 60MB TIFF files, please let me know. Thanks.

[pascal_meheut]

Whatever software you use to look at your jpeg out of C1 does not use the same screen profile as C1. This is the most probable cause.

[ericperlberg]

I'm not a regular user of C1 but I had a quick look. In your preferences click on Color Management. Then click on destination. What do you have Rendering Intent and Rendering Quality set to?

 

Imagine two balloons, one blown up 1/3 larger than the second. Now imagine that each is a colour gamut, ie, the volume of each balloon represents a collection of colors. The centre line of the balloon represents the range from black through dark to light and finally white. The outside surface of each balloon represents the most saturated colours.

 

So, for example, imagine a point on the surface of the larger balloon representing a very saturated yellow. But that colour doesn't exist on the smaller balloon. So how do you represent the saturated yellow of the larger balloon on the surface of the smaller balloon?

 

That is the question that Rendering Intent attempts to answer.

 

Your Leica profile is like the larger balloon, it can theoretically contain colours (a saturated yellow for example) that don't exist in Adobe RGB, the smaller balloon.

 

Although C1 have listed 4 rendering intents for completeness, only 2 are of relevance to photographers; Perceptual and Relative Colorimetric. Remember, both of these "intents" are rules for translating the saturated yellow in the larger balloon to the smaller one.

 

Relative Colorimetric Intent says:

For every colour that exists for in the larger balloon that also exists in the smaller, just map the one to the other so they're the same. However for the colours which exist in the larger balloon (the Leica profile) that don't exist in the smaller balloon (aRGB), simply map the larger more saturated colour on to the closest colour of the smaller balloon.

 

The result is that colours that exist in both balloons (profiles) stay the same (totally accurate) and the saturated colours in the Leica balloon are "unsaturated" down to the closest colour on the aRGB balloon. I suspect this is the setting you have set in your prefs (relative colorimetric).

 

Perceptual Intent says:

In order to preserve the perceived relationship between all the colours of the Leica balloon (ie, those saturated colours in relationship to the less saturated ones) when converting to the aRGB balloon, I'm going to rearrange all colours in your image a bit so that I can maintain the perceived levels of saturation even though they don't exist in the destination space.

 

The result, slightly less accurate colours all the way through the destination image in comparison to the original but the overall "feel" remains the same or very similar.

 

Try Perceptual and see if it solves the problem.

 

There is no right and wrong choice. Don't make up a rule, It's an image by image decision (at least for professionals) depending on the demands of the photo involved.

 

Hope that was what the problem was...

[delander †]

Eric,

That is a great explanation. Helped me at least to understand this colour mapping. I could not find a choice of rendering intent in C1LE however. Perhaps you need the full version. I have always gone for relative colourmetric in photoshop, perhaps I will look a little harder at perceptual.

 

Thanks

 

Jeff

[ericperlberg]

Jeff, I also only have C1 LE. In the Capture1 menu (I'm working on a Mac so if you're on a PC prefs may be in a different place) choose Preferences. Now click on the Color Management tab. Now you have 4 options, Camera, Monitor, Destination and Profile Management. Click on Destination. That's where you choose rendering intents. If you're on a PC and you can't figure out where the Rendering options are, go to the HELP menu and choose C1 help. One of the main chapters is color management. Click on that and scroll down a bit and it tells you about rendering intents.

 

Eric

[delander †]

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Eric,

 

Thanks but it appears to be different on a PC. The preferences do not have a color management tab. Color management is under workflow and you can choose to embed or convert when exporting to tif. There are no options for rendering intent and no reference to it in the help file.

 

So I tend to embed the Leica profile and then do the conversion in PS

 

Perhaps it will improve in version 4. I think C1LE needs to have a few more features if it is to keep up at all with Lightroom.

 

Jeff

[marmelade]

hello,

 

all of the above is very good explained but what i find often that one forgets when it comes to jpgs and colorspace and pc is that: until now (vista, which i personally cant vouch for=) windows has been quite not "fully" colormanaged therefore if one views a jpg with a argb colorspace in lets say explorer it will look less saturated (less punchy)

 

so since most pcs arent showing the correct colorspace one solution is to convert your image in pshop to srgb which most pcs shows "closest" to the original.

 

so before you save for web or as a jpg for viewing (not printing cause there argb/other is a wider colorspace and is possible to achive) do a convert to profile -> srgb

 

then you may feel thepicture is more what you have seen in c1/le/ps

 

(btw im new to this forum so hello =)

 

are

[B&W]

Velkommen til forumet, Are

 

So what you suggest is to save two versions of the file, one for screen and one for print

Do I understand you correct?

[ericperlberg]

Velkommen til forumet, Are

 

So what you suggest is to save two versions of the file, one for screen and one for print

Do I understand you correct?

 

In my workflow I keep 3 versions.

1) The original RAW file in case I want to rework the file in a different manner later for example in case technology and software improve.

2) The best print version I can make (generally in AdobeRGB or ProPhotoRGB colour space) saved as a psd or tiff file. This file includes sharpening, tonal corrections, dodging/burning and other darkroom like adjustments. I soft-proof this file using my custom icc printer profiles as one's printer is likely to have a significantly different colour space from AdobeRGB or ProPhoto. When I get it looking the way I want I save this for future printing in a separate folder for just such files

3) A resized jpg in sRGB for the web. Printing files requires large file sizes and wide colour gamuts. The web requires smallish files and as most web browsers can't read attached profiles, its best to save these files in sRGB which is a small colour gamut compared to aRGB or ProPhoto but its appropriate for the web because most monitors can only display roughly speaking the sRGB colour gamut. Without attached profiles, web images fall back on the monitor profile. This sRGB file will go into its own folder for web images.

 

In Photoshop you can either ASSIGN a profile or CONVERT to a profile.

 

Assign leaves the original numbers and is preferred for your print file. I assign (or tell Lightroom or Adobe Camera Raw to assign) the working colour gamut of my choice.

 

However when saving a jpg for the web its important to use Convert to Profile as most web browsers are not profile aware and default to the monitor profile (which is why we use sRGB). But convert to profile throws away any unused information so conversions from Adobe RGB or ProPhoto to sRGB winds up tossing a lot of very useful information.

 

Note:

RAW files opened in Lightroom and Aperture are displayed in very wide colour spaces. I don't know about Aperture but Lightroom uses a version of ProPhoto (it assigns ProPhoto which means it doesn't change the raw data it merely filters the raw data as though it had been converted). When you print out of Lightroom or Aperture you can choose the custom icc profile you want and Lightroom or Aperture will print the file in that colour space (Aperture has soft-proofing to check that the print looks the way you want it. Lightroom currently lacks this feature so I print out in Photoshop). You'll be given the option of rendering intents in all 3 programms.

[marmelade]

Heisann Jarle!

 

Jepp that is what i do (and have done for several years) also with other digital imaging devices.

 

Opening raw -> converting to tif (since i dont use ACR) then open i pshop edit what i need save as a original (.psd) or a tif for sending to print and also converting to srgb and saving a small web/screen version jpg.

 

then i have left in my system, the original raw file (negative) and the postprocessed one (.psd) and one for screen viewing (.jpg)

 

(actually alot of online non pro printing shops online, will give u closer results if u give them a srgb file instead of an argb/prophoto.)

 

This is just my version of a workflow, i also look forward to a new C1 4.0 but im getting a little impatient seeing what nice workflow possiblities aperture and lightroom has.

 

but aslong as my c1 results is how they are now i wont change atleast yet..

 

(ok i must admit.. i installed LR yesterday .. but its just something about the interface that is "wrong" or new