CS4 Filter Question

[Ed Vatza]

I have CS4 installed on my iMac and have been having a problem that I don't understand.

My workflow starts with a RAW file converted to a .dng file and taken into Lightroom 2.0 where I make certain adjustments depending on the image. From there, I export the file to Photoshop where I do "more advanced" processing before saving the image back to Lightroom as a .tif. This is my basic work flow on the iMac/LR2/CS4 combo.

I am using ProPhotoRGB color space. It is recommended to run it at 16 bits per channel. Which I have done. In LR2 under preferences, I have selected ProPhotoRGB and 16 bits per channel. In CS4 under Image - Mode I have 16 bits selected.

When I do that in CS4, I always find that only certain filters are available to me while others are not. Available filters include some but not necessarily all of Blur, Distort, Noise, Render, Sharpen, Stylize, Video, Other. UNavailable filters include all of Artistic, Brush Stroke, Pixelate, Sketch, Texture.

If I manually switch the Image - Mode setting in CS4 to 8 bit, the unavailable filters become available.

My question is why are they not available in 16 bit? And should I change the settings in LR2 to export at 8 bit instead of 16 so I don't have to do it manually every time I want to use a filter in CS4 even though the recommend is 16 bit? And finally, if so, what is the use of 16- or 32-bit, if certain features only work with 8 bit?

[Trevor Hughes]

There are a limited number of processing options in 16 bit, as you are finding. Basic processing is available in 16 bit, levels, curves etc. So there is a benefit. The number available has increased with CS4 and maybe, more will be accessible in future versions, but for now, if you want to use the artistic filters you will have to convert to 8 bit.
For the benefits take a look at http://www.photoshop-tutorials-plus.com/8-bit-and-16-bit.html

[arash_hazeghi]

Ed, that is not your problem it is an Adobe limitation :)

[Ed Vatza]

Thanks folks. It's nice to know that at least something isn't my fault!

Trevor, I read the article you provided the link for and I have another question.

OK, I understand that i should use 16-bit wherever possible and only switch to 8-bit when necessary - like using those filters that are grayed out otherwise. But the last line reads "and only change to 8-bit mode for the final output. Printing has to be done in 8-bit" (italics mine). Why? As far as I know I have been printing in 16-bit. At least I have not made any changes manually when going to print mode in either LR2 or CS4. (For the record, I am printing on an Epson 3800.) Nothing untoward seemed to happen (I think).

[Trevor Hughes]

Thanks folks. It's nice to know that at least something isn't my fault!

Trevor, I read the article you provided the link for and I have another question.

OK, I understand that i should use 16-bit wherever possible and only switch to 8-bit when necessary - like using those filters that are grayed out otherwise. But the last line reads "and only change to 8-bit mode for the final output. Printing has to be done in 8-bit" (italics mine). Why? As far as I know I have been printing in 16-bit. At least I have not made any changes manually when going to print mode in either LR2 or CS4. (For the record, I am printing on an Epson 3800.) Nothing untoward seemed to happen (I think).

My understanding is that Windows printing doesn't support 16 bit. I read it somewhere, but can't find it now - sorry.
I suspect there are others here more knowledgeable about this than me. I believe Macs can, with the right printer drivers.

[arash_hazeghi]

My understanding is that Windows printing doesn't support 16 bit. I read it somewhere, but can't find it now - sorry.
I suspect there are others here more knowledgeable about this than me. I believe Macs can, with the right printer drivers.

Windows can print 16Bit TFF files with no problem. In practice with most printers you won't be able to tell a difference though.

[Trevor Hughes]

Windows can print 16Bit TFF files with no problem. In practice with most printers you won't be able to tell a difference though.

I think the question is can it print to 16 bit depth. I've found quotes from people like Scott Kelby and Jeff Schewe that say no Windows can't http://www.digitalphotopro.com/software/image-processing/photoshop-cs4-takes-off.html
Extract from above "Windows users may be a bit ticked off as well. Mac users with at least Leopard (10.5.x) can print 16-bit-per-channel directly to those printers that can accept the 16-bit print pipeline. Windows, neither XP nor Vista, doesn’t support a 16-bit print pipeline."
However, we all know that quotes aren't always accurate and that it is possible that support has been added now.
:)
I agree with you though the difference is probably insignificant.

[David Thomasson]

You already got the answer to your first question: Not all filters in PS work in 16 bit mode.



should I change the settings in LR2 to export at 8 bit instead of 16 so I don't have to do it manually every time I want to use a filter in CS4 even though the recommend is 16 bit?

I'm not sure, but it sounds like you're converting from 16 to 8 bit, running a filter, then converting back to 16 bit. If so, there's no advantage in doing that.
16-bit to 8-bit is a one-way street; once you convert down, you've lost the additional image data you had with 16-bit.