How to Convert an Embedded sRGB Color Profile Image to an 8-Bit Gray-Scale Image

[caleb5]

I have a .TIF image that has an Embedded sRGB Color Profile and I want to convert it to an 8-Bit Gray-Scale .TIF image.  Would anyone know how to do this in Photoshop CS3?  Can I do this by the Image > Mode > Grayscale menu?

Thanks in advance.

[D Fosse]

Convert to Profile. Image Mode does the same thing, but doesn't give you a choice - it converts to whatever you have set up as working gray. That's fine if you know that's the profile you want.

Grayscale works just like any other color spaces. It's just one channel instead of 3 or 4. The icc profile defines the values.

Personally I try to avoid grayscale, because support in other applications is very poor. To my knowledge only Photoshop and Acrobat treat grayscale correctly, by honoring the embedded profile and converting correctly for display or printed output. In all other applications, all bets are off, and there's a high likelihood of random tonal shifts. Even Illustrator and InDesign are lacking here.

If I have to use grayscale for offset print on the black plate only, I prepare a CMYK file (using the appropriate CMYK profile) with CMY empty and all content in the K channel. Such a CMYK file is displayed accurately in Photoshop and always treated correctly on press.

[JJMack]

Yes Grayscale is not used much.   There are many ways to convert a color image to Black a White and you have more tools to control the conversion process.

https://www.google.com/search?q=adobe+photoshop+convert+color+picture+to+black+and+white&oq=Photosho...

[JJMack · Accepted solution]

Yes

When you open your tiff that has and embedded sRGB color profile in Photoshop.  It will open as a three channel document the is in SRGB Color space.  If you use menu Image Mode Grayscale the document will be converted to s single channel Grayscale image and convert to a Dot Gain 20%  profile.

Photoshop is a document editor not a file editor your Tiff file on disk is still  a sRGB Color image.   The document in Photoshop is not.  When you save a file for the document the File will have A grayscale  image Profile Dot Gain 20%.  I added gray to the document name when I save that tiff file or PSD or PNG.  Whatever you use in Save AS.

I use  a newer Photoshop I no longer have CS3 installed.  Photoshop has not changed in that area

[caleb5]

Thanks for the replies everyone.  So if I want to convert my image file to an 8-bit grayscale file (not just the way the image looks when viewed in Photoshop, but change the file) Photoshop is not the right tool for that Job.

Thanks everyone.

[JJMack]

caleb5  wrote

Thanks for the replies everyone.  So if I want to convert my image file to an 8-bit grayscale file (not just the way the image looks when viewed in Photoshop, but change the file) Photoshop is not the right tool for that Job.

Thanks everyone.

Photoshop will have not problem saving an 8 or 16 bit grayscale image.  If you must have a grayscale image file.  You may want to first convert your color image to Black and White with Photoshop features that enable control how the colors are converted then convert  your Black and White RGB image to grayscale.  I would not write that Photoshop is not the right tool.  Its the tool  I have.

[D Fosse]

caleb5  wrote

So if I want to convert my image file to an 8-bit grayscale file (not just the way the image looks when viewed in Photoshop, but change the file) Photoshop is not the right tool for that Job.

That's the exact opposite of what I was trying to say. Photoshop is exactly the right tool for that job - not only that; it's pretty much the only application you can use to convert RGB into grayscale. Very few applications can do that.

You just need to consider which grayscale profile you want. If your reference is screen, the safest choice is probably gray gamma 2.2.

Grayscale support everywhere else is mostly non-existent. In almost any application you can think of, it will most likely not be printed or displayed correctly. Photoshop is the only widespread raster image editor that I know of that will treat grayscale correctly.

[caleb5]

Thanks for the reply.  It's not quite the appearance of my image I want to change, it's the format in addition to that.  I want it to be an 8-bit greyscale image, not just any ordinary greyscale image.  What profile would you recommenced using in that case?

[D Fosse]

You're mixing things up here. The bit depth is something else entirely, not related at all.

Again, to make a true grayscale file, "Convert to Profile". If you don't know which grayscale profile to choose, I'd recommend Gray Gamma 2.2. This removes all color information and leaves only a single channel.

Completely separate from that, you can convert from 16 bit depth to 8 bit depth, or vice versa. This is a separate menu item under Image > Mode.

[caleb5]

Sorry for the mix up.  I'm kinda new to Photoshop.

Thanks, I wasn't able to locate the 8-bit option under Image > Mode, that's what I needed to know.

Thanks a lot!