16bit image saving problems in CS2 (9.0.2) XP(SP2)

DM
Posted By
DRMR_MRK
Sep 2, 2006
Views
564
Replies
12
Status
Closed
I am layering an 8bit RGB image into a 16bit RGB image. Everything is fine on screen, I have a 16bit image on screen after the merge (its a printer profile target so I can read off the values easily to confirm its really 16bit). However when I save and reload the image has 8 bit values (though it still appears as a RGB/16# image).

I have tried everything, merging both ways, saving as PSD, Tiff etc. Nothing seems to enable the image to save and reload as a true 16bit image.
Maybe this is a known bug but I can’t find a reference to it anywhere.

I am using 9.0.2 on XP+SP2

Any ideas much appreciated. Files are not very big (about 32K each) I could email them to someone willing to help me.

Txs,

Mike
Related Tags
16-bit image problems save

Master Retouching Hair

Learn how to rescue details, remove flyaways, add volume, and enhance the definition of hair in any photo. We break down every tool and technique in Photoshop to get picture-perfect hair, every time.

CN
Cybernetic Nomad
Sep 3, 2006
Hi,

Use of the proper vocabulary will help you achieve clarity.

I am layering an 8bit RGB image into a 16bit RGB image.

Do you mean you are converting an 8-bit image to 16-bits?

However when I save and reload the image has 8 bit values (though it still appears as a RGB/16# image).

Where do you see these 8 bit values? the info palette? If so, are you sure you enabled 16 bit values in teh palette options?

If the header of the image reads RGB/16# then the file is in 16 bits…
C
chrisjbirchall
Sep 3, 2006
If so, are you sure you enabled 16 bit values in the palette options?

Mike: Click the little eyedropper icon in the info palette and select 16 bit from the fly-out.

its a printer profile target

You are aware, aren’t you, that printers currently only handle 8 bits per channel images?

You can feed a 16 bit image to your Inkjet and it will convert it on the fly. Most Photo labs, however, will simply reject images which are sent as 16 bit.
DM
DRMR_MRK
Sep 3, 2006
Thanks for the responses.

I have 16 bit view enabled in the info palette that’s what I am using to measure the wedges. I have a 1024 (10bits) step wedge that goes down 1 step at a time. Before I save the merged 8bit+16bit file it still does 1 step per wedge. After I save and reopen it now has 4 steps at the same level and then steps down. Basically its clipping my 10bit data to 8bit even though I have it in a 16bit file. Note if I just save and reopen the original 16bit data file, it preserves the data in 16bit. So this problem has something to do with the fact that I am layering another image into it.

The 8bit image is a frame around the 16bit data and I am merging them with a mask.

Here are the steps I take.

1) Open 8bit file.
2) Open 16 bit file
3) Convert 8 bit file to 16 bit.
4) Drag 8 bit image (now 16bit in step 3) over 16bit one and it forms a new layer.
5) make a mask so the 8 bit image sits around the 16 bit step wedge
6) flatten image. Now I have a 16 bit image with 10 bit values as measured in the info palette (1024 step wedge).
7) Save the file
8) Open the file and the image is 16bit but the data has been clipped to 8bit as measured in info palette (set to 16 bit.) !!

This could easily be a photoshop bug as you wouldn’t notice this unless you were doing something very measured, like I am.

Mike
C
chrisjbirchall
Sep 3, 2006
Mike. If you’d like to post these two files somewhere on your web space or email them to me: chris AT beautyphoto DOT co DOT uk I’ll see if the same happens here.

Chris.
DM
DRMR_MRK
Sep 3, 2006
Chris,

Txs for the offer. Turns out I misread how large they were 12Mb+ and so I’ll try some more thoughts I had overnight and see if I can fix this myself.

Mike
BL
Bob Levine
Sep 3, 2006
12 megs isn’t that large. Try www.yousendit.com.

Bob
C
chrisjbirchall
Sep 3, 2006
they were 12Mb+

As they are apparently only greyscale wedges, you could send me a scaled down version, or as Bob suggests use YouSendIt. Or, if you have access to any web space via FTP, just post them there so I/we can download them.

By seeing the effect we can offer better advice.
WR
William_Robert_Hill
Sep 5, 2006
I like to question the statement of all inkjet printers can currently print only 8 bit images. I print directly from 16bit photoshop. CS2 to an epson printer and I see a major difference between the 16 bit and 8 bit images. You could be right that most printers on the fly convert to 8 bit however my findings are different than yours.
CN
Cybernetic Nomad
Sep 5, 2006
What printer?

(inquiring minds want to know)
MD
Michael_D_Sullivan
Sep 5, 2006
The WinXP API used to send picture data to a printer driver sends an 8-bit-depth 3-channel (RGB) bitmap. That’s all the driver expects and that’s all PS sends. The only way to send 16-bit-per-channel data to a printer is to use a specialized interface between the program and the printer. It is possible that RIPs do this, I don’t know. But if you are sending to the same standard Windows printer driver that is used by other programs, all you can send is 8-bit. Any conversion will presumably be done internally by Photoshop.
L
LenHewitt
Sep 5, 2006
I like to question the statement of all inkjet printers can currently
print only 8 bit images. <<

Question it all you like, William, but that is the current position.

Try a Google on "48-bit printer driver" if you desire confirmation.
WR
William_Robert_Hill
Sep 5, 2006
Thanks to all three of the answers to my 16 bit print question. The printer is a low end Epson Stylus Photo R220.
Print selections win gamma 2.2 adobe rgb premium luster paper Win xp pro latest drivers updated as well as CS2 current. Gentlemen if you have the trained eyes that can see a difference between 35mm film print as compared to a 6×7 film print then you will have no trouble seeing the difference. Im not a salesman from epson. I just want to make better prints. I also note you can over saturate in 16 bit prints where as printed in 8 bit they will not.
Thanks to all for the reply and the google search was a good one too. Darn shame if everyones theory is right that windows reduces color information down to 8 bit. Guess I can start shooting low end jpgs instead of raw to 16 bit for my best images.

How to Master Sharpening in Photoshop

Give your photos a professional finish with sharpening in Photoshop. Learn to enhance details, create contrast, and prepare your images for print, web, and social media.

Related Discussion Topics

Nice and short text about related topics in discussion sections