Photoshop and 16 bit TIFFs

[cmM]

After I convert RAW files to 16 bit TIFFs and open them in Photoshop 7, I can do very little to my pictures, because most tools don't work with 16bit/channel images, and it advices me to convert to 8 bit/channel.

How do I go around this ? ???

[BDM]

As I understand it, I believe that all you can do is upgrade to Photoshop CS which now has support for 16 bit files in most functions.

Bruce

[Roger_Cavanagh]

A great article by Bruce Fraser: "Out of Gamut: You Can't Do This to High-Bit Files in Photoshop (or Can You?)" explaining how to get round some of the limitations of working with 16-bit images in Photoshop. Here's his conclusion:

You can't make complex selections with feathering and transparency in high-bit files. But you can transfer such selections to high-bit files.

You can't adjust layer blending and opacity in high-bit files. But you can fake it with the History brush.

You can't paint on high-bit files with the Paintbrush tools. But you can fake it with the History brush.

You can't copy and paste pixels between high-bit images. But you can move pixels from one high-bit image to another with the clone tool.

Read the article here (http://www.creativepro.com/story/feature/16097-1.html).

Regards,

[cmM]

That should give me a clue about what's goin on. Thanks a lot for the article.
Photoshop CS has better support for 16 bit images ?

[Roger_Cavanagh]

Photoshop CS has better support for 16 bit images ?

Much better - almost everything. Two things off the top of my head that aren't are the new lens blur filter and the new pano stitching facility. But layers, are now 16-bit - you never saw anything eat space and memory so fast. :)

Regards,

[chris.bailey]

Just my thoughts and I may well be wrong -

The advantage of 16 (12?) bit images from RAW is the larger colour space. As most printers are not capable of such a wide gamut there is little advantage at print time. If you process 16 bit through levels and colour balance the histogram remains more intact. If you then change to 8 bit for further processing there is little print benefit from staying in 16 bit.

[Roger_Cavanagh]

Just my thoughts and I may well be wrong -

The advantage of 16 (12?) bit images from RAW is the larger colour space. As most printers are not capable of such a wide gamut there is little advantage at print time. If you process 16 bit through levels and colour balance the histogram remains more intact. If you then change to 8 bit for further processing there is little print benefit from staying in 16 bit.

16-bit isn't giving you a larger colour space. It gives you more numbers - 4096 values per colour channel vs 256 - but Adobe RGB is the same size. As far as printing is concerned, what working with 16-bit files does is allow you to print the best 8-bits. (I stole that from Andrew Rodney. :) ) If you can afford the space and the extra processing demands, you may as well stick with 16-bit and let the 8-bit conversion be handled by Photoshop (or Qimage or...) at the time of print - you can always whittle away a bit more wood, but you can't, etc. :)

Regards,

[cmM]

So, bottom line is, it'll end up as a 8 bit image anyway. Plus according to that article you "can" manipulate the 16bit image in photoshop 7, but what you're doing is putting 8bit "modifications" on top of the 16 bit image.... :?
This brings me to another question: Should I convert straight to 8 bit TIFFs (from RAW), or should I change to 8bit mode on PS ? Is there a difference at all ? (btw I'm using C1 to convert)

[Roger_Cavanagh]

So, bottom line is, it'll end up as a 8 bit image anyway. Plus according to that article you "can" manipulate the 16bit image in photoshop 7, but what you're doing is putting 8bit "modifications" on top of the 16 bit image.... :?

Errm? I don't follow your logic here. 8-bit dupes are used to do things like create masks, but all the edit ops are still 16-bit.

This brings me to another question: Should I convert straight to 8 bit TIFFs (from RAW), or should I change to 8bit mode on PS ? Is there a difference at all ? (btw I'm using C1 to convert)

If you intend to make levels and curves adjustment, you are better in 16-bit because the extra colour numbers give more wiggle room. With PS7, of course, you can't use layers, but even with PS CS you should flatten any layers before conversion to 8-bit otherwise you lose the benefit of the 16-bit manipulation.

If you have PS CS and work with 16-bit layers and Print with Preview, PS CS will flatten all layers, do an optimal conversion to the print space and 8-bit automatically and you still have the 16-bit version for any further processing.


Regards,

[cmM]

I see the reasoning now...
Guess I should upgrade then. I'll try it out first, and play around with it a little.

Thanks a lot for the info. It's appreciated deeply.