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[OM] Re: Sixteen Bit Scanning and Photoshop

Subject: [OM] Re: Sixteen Bit Scanning and Photoshop
From: Moose <olymoose@xxxxxxxxx>
Date: Wed, 28 May 2008 22:50:06 -0700
Winsor Crosby wrote:
> ....
>
> I was intrigued that you can open TIFF or JPEG files in ACR and tried it with 
> TIFF files from the scanner because I like some the of tools in ACR. It works 
> fine except when the file gets transferred to Photoshop where it ends up 
> being converted to an 8 bit depth file. 
I don't think it is being converted in the process of being transfered. 
You don't say what scanner and software you are using. In the case of 
the CanoScan software for my 9950F, I can leave the 16 bit box checked, 
but it only outputs 8 bit files to disk. If I have it send the files to 
PS instead, they are 16 bit.
> I also tried the scan using Vuescan and saving the file as an Adobe digital 
> raw format in 16 bits. 
You have to set 16 bit in both input and output tabs in VueScan. If 
either one is 24 bit RGB, you get an 8 bit output.
> It also opens fine in ACR, but the file also gets converted to 8 bits upon 
> transfer to Photoshop. It seems odd since you can open a sixteen bit TIFF 
> file in Photoshop without a problem.
>
> Am I missing something? Or is what I am trying to do just not possible? 
Certainly it is possible, if your scanner software actually writes 16 
bit files. I just opened a 16bit TIFF from VueScan, Bridge => ACR => PS, 
and it's 16 bit in PS.
> Just to be clear, what I want to do is:
>
> 1. Scan and save an image in 16 bits.
>   
Make sure it is actually 16 bit. For a TIFF, multiply the pixel 
dimensions together, times 3, times 2 (for two bytes per pixel per 
color). The file I just tested is 35mm film @ 4000dpi, and about 123mb. 
An 8 bit version would be about 62mb.
> 2. Open it in ACR and adjust it.
>   
ACR has an option for output bit depth. As I recall, it may be different 
for different file types. Be sure it is set to 16 bit. The setting is in 
the line of specs below the image.
> 3. Open the file in Photoshop in 16 bits.
>   
A I say, works for me. I don'y know enough about DNG to trust it for a 
test. I'd work with TIFF first. When that's working, you can try DNG.
> Any ideas?
>   
Apparently, I do.

Moose

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