Color Management question: a JPEG from a museum

[MarieMeyer]

I have downloaded some open-access photos of famous paintings from a museum. I assume they are color correct. But they have no embedded profiles. I need to open them in Photoshop to do some cropping and straightening. Then I'm going to place them in Illustrator, and from there they will go to InDesign, for print production.

My working spaces are Adobe RGB and GRACoL13. 

Should I assign the working profile when opening them, and then output them as PNGs with that profile embedded?

[Conrad_C]

The RGB profile you should assign is the one that you are certain is the RGB color space the images were exported with. That means assigning your working RGB profile might not be a safe choice here, because most images are exported for web sites using sRGB, but your working space is Adobe RGB.

• The best way is to compare one of the downloaded images against the original painting, while changing the assigned profile to see which one matches the original the best. Of course, you probably don’t have access to the original paintings to do that comparison, unless it’s practical for you to travel to the museum, so… 
• The next best thing would be to contact the museum and see if you can get the export color space from their web team. If that isn’t realistic… 
• You can compare what the downloaded images look like with sRGB assigned vs Adobe RGB, and see if one of them looks more realistic. For example, you can do this using the Assign Profile dialog box, switching profiles with the Preview option turned on. Since most web images are exported as sRGB, it would be highly unusual for them to be exported as Adobe RGB without a profile, so chances are the painting colors should look the most plausible when interpreted as sRGB. If it somehow does not, and if this is going to be an important fine art publication, at this point it would be a good idea to try and talk to the museum’s web team to get some clarity on how they exported. 

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@MarieMeyer wrote:

…and then output them as PNGs with that profile embedded?

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For print publication, PNG could be used, but is unusual. Typically, an InDesign print publication would use images in PSD/Photoshop format if you wanted full control over layers and transparency in InDesign; but TIFF, JPEG, and less commonly PNG can also be used.

Furthermore, if it is a modern prepress workflow, the images would be left as RGB with embedded profiles, and imported into InDesign that way, with the conversion to press-specific CMYK done at print time. If it is an older CMYK print workflow, then the images might need to be converted to CMYK before handoff, but if so, you must use the exact profile required for the specific printing process; if that is GRACoL13 then use that. If you aren’t certain about the details of this paragraph, the printing company should be able to clarify which workflow to follow and therefore which export settings would work best.

[MarieMeyer]

Thanks. If I assume that the originals were intended for sRGB, would I assign sRGB or assign sRGB and then convert to Adobe RGB? 

 

[Conrad_C]

If the web JPEG images were determined to be exported in sRGB, I would normally assign sRGB and leave them that way. Converting to Adobe RGB won’t improve the original colors. One reason to convert to Adobe RGB might be if you were adding additional elements with colors outside sRGB, but if all you are doing is straightening and cropping, I can’t think of a reason why they need to be converted to Adobe RGB.

The main purpose of the working space in Photoshop is just to be a default for documents that don’t already have a profile, especially blank documents created with the File > New command. If an image already has an appropriate profile, it should usually continue to use that; so the working space isn’t really used then.

20 years ago, the working space was used more often because the workflows at the time were more  likely to require all images to be converted to the same color space.

But in the color-managed workflows of today, it’s more common to leave all images in their original color spaces while editing. For example, if you open an sRGB image from the web alongside an Adobe RGB image from a scanner and a ProPhoto RGB image converted from a camera raw file, all three image documents will be open in Photoshop in their own color spaces.

They can all be dropped into the same InDesign document, and at output time (print, export to PDF, or export to web/EPUB), InDesign can convert all of them to whatever RGB or CMYK color space is required for that job. By not converting too soon, the images retain the flexibility to be converted to a different color spaces as needed when sent to a range of RGB and CMYK destinations.

[TheDigitalDog]

Assign sRGB, if the image looks "OK" it's fine and most likely sRGB. 

There is no reason to convert to Adobe RGB (1998). Leave it in sRGB. 

This may help further: 

See: http://digitaldog.net/files/PhotoshopColorSettings.mp4

Photoshop CC Color Settings and Assign/Convert to Profile video

[NB, colourmanagement]

Marie

Conrad has taken the time to give you a good through explanation of what you should do and why. 

Digital Dog too.

I have to add that it's ridiculous to share images with no embedded profile. Even if they are free.

The "default" colour space people use seems to be sRGB [especially for web] partially because that's how Photoshop is set when installed. 

I also suggest you should assign sRGB and if the saturation looks right (on your calibrated screen) go no further,

[if the images look desaturated then try Adobe RGB - or ask the museum)

converting an sRGB file to Adobe RGB is pointless you are taking a shotglass of booze and pouring into a small wineglass.

That shot of scotch is not going to expand to fit the wineglass. 

Your own screen is calibrated? Tough to make any decisions based on appearance, if not

  I hope this helps
neil barstow, colourmanagement net :: adobe forum volunteer
google me "neil barstow colourmanagement" for lots of free articles on colour management
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