Hi Paeon,
Using Photoshop you can convert (not assign) source profile of each image to “standard” sRGB for Web use.
At this point you can choose to save the JPEG file with or without profile.
Numbers have been converted.
Disabling (assigning color profile None) to images is a BIG error because images received can have a lot of different profiles.
To understand the impact of Color Management follow this example:
Get a Raw file and generate using Camera Raw or similar sw, 3 different files with different color profile:
Raw → Adobe RGB (1998)
Raw → sRGB
Raw → ProPhoto
Save this 3 files as JPEG with embedded profile. They “look the same” (they are very similar) opened in Photoshop.
Embedded profile is used as source profile and real time conversion is executed between image profile and monitor profile (Photoshop Monitor Compensation, what our eyes see).
Now open each one and assign Color profile None (Don’t Color Manage the file).
Save files with different name.
Now drag and drop each couple of file to browsers.
Comparing the version with embedded profile and the version without color profile, colors change a lot (images can be completely different) with file related to ProPhoto and Adobe RGB (1998).
So, the summary is: manage always color profile, converting it to final destination (for Web use the standard is sRGB) and keep profile (it’s only few bytes of size). If you convert to sRGB for web use you can also choose to save files without profile. But the important thing is that the previous “Convert to Profile” has changed numbers to keep the same “colorimetric” perception of image.
Now, all 3 browsers (Safari, Firefox, Chrome) can handle color profile embedded inside images basically working like Photoshop.
But until few months ago, Google Chrome was unable to do this, so best practice, general speaking, is to repurpose image for web use converting (not assigning) profile to sRGB.
For do this you can use Photoshop or also SIPS that is a CLI, very fast, embedded in every OS X.
SIPS example (Match and Remove) are located in /Library/Scripts/ColorSync/ folder.
If you need to manage also conversion from CMYK to RGB to generate Preview and Thumb for Web use, Photoshop has higher quality than SIPS because can use BCP (Black Point Compensation ) that is not available under ColorSync. Also the downsampling quality is much higher in Adobe Photoshop.
Stefano - Ame
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Operating System: Mac OS X (10.8)