Inspiring

Answered

Color change between 8-bit and 16-bit

Forum|Forum|4 years ago
August 8, 2021
4 replies
4189 views

This was a surprise. I copied a layer from a 8-bit file with color blocks, including three brown ones named coffee brown, dark chocolate brown, and mahogany. In other words, they're unmistakably brown.

I copied the layer into a 16-bit file. All the colors are a little bit different, except that the browns turned red.

I color sampled them, and Photoshop says they're the same colors. Coffee brown is 184/77/76 in the original 8-bit and when copied into the 16-bit document. However, when I screengrabbed them, Photoshop reports the 16-bit coffee brown is RGB 250/32/79.

I thought, if anything, the 16-bit color would be more accurate or complex than 8-bit, but that's clearly not the case, at least when it comes to browns. I'm using an Acer CM3271K (4K UHD IPS, 99% Adobe RGB, Delta E <2 color accuracy).

I don't know how to handle this. I can't just avoid using brown.

Scott

Dear_Adobe_08082021.zip

Windows

This topic has been closed for replies.

Correct answer D Fosse

This has nothing to do with 8 bit vs 16 bit. It's lack of color management procedure.

First, make sure the file has an embedded color profile. It's not so important which one, as long as there is one. Never work with untagged images (no color profile). If you need a different color space than the embedded, convert.

Second, screenshots are a special case. A screenshot is no longer in the original document color space. The numbers have been converted into the monitor profile, into monitor color space.

To correctly handle a screenshot, always assign your monitor profile first, then convert into whatever standard color space you're working in.

c.pfaffenbichler

Community Expert

Are the questions »What are the two images’ Color Spaces?« and »What are Photoshop’s Edit Color Settings?« too taxing to answer?

scotwllmAuthor

Inspiring

I've asked you politely three, now four, times to not respond to my posts.

c.pfaffenbichler

Community Expert

@scotwllm wrote:

I've asked you politely three, now four, times to not respond to my posts.

You think I learn the names of rude Forum posters by heart in order to avoid trying to help them in other threads they might start?

Because you seem to refer to another thread …

But back to the issue at hand: Was the color change owed to the two images having different Color Spaces (or one being unprofiled)?

D Fosse

Correct answer

Community Expert

This has nothing to do with 8 bit vs 16 bit. It's lack of color management procedure.

First, make sure the file has an embedded color profile. It's not so important which one, as long as there is one. Never work with untagged images (no color profile). If you need a different color space than the embedded, convert.

Second, screenshots are a special case. A screenshot is no longer in the original document color space. The numbers have been converted into the monitor profile, into monitor color space.

To correctly handle a screenshot, always assign your monitor profile first, then convert into whatever standard color space you're working in.

c.pfaffenbichler

Community Expert

If only »Document profile« was the Status Bar default then one might be able to gather the relevant information from screenshots right away in cases like this …

D Fosse

Community Expert

Indeed. That's a lot more useful than image sizes. And it would save us a lot of time.

c.pfaffenbichler

Community Expert

»However, when I screengrabbed them, Photoshop reports the 16-bit coffee brown is RGB 250/32/79.«

What are the readings for the 8bit image?

In a Color Managed situation it would seem very unlikely that a screenshot would display the same RGB-values as in the original profiled image (except for special cases close to extremes).

What are Photoshop’s Edit Color Settings?

c.pfaffenbichler

Community Expert

What are the two images’ Color Spaces? (I mean »Color Spaces« as in ICC Profiles, not »Color Modes« as in »RGB«.)

Please set the Status Bar to »Document Profile« and post screenshots of the source image and the receiving image.

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