Grayscale Gamma 2.2 & QTR

[DHodson]

I've been using Corel PSP X8 for photo editing and am starting to set up to use Roy Harrington's QTR and the piezography inkset. My understanding is that QTR expects a grayscale Gamma 2.2 TIFF but PSP X8 doesn't have a selection for greyscale Gamma like Photoshop does. It could be that the default for PSPX8 (Windows version) is 2.2 but their support desk couldn't tell me.

I'm okay just going ahead and seeing how it works out but I was wondering if anyone had any thoughts or what others were using. Is there editing software out there (other than Photoshop) that lets me select the grayscale Gamma to work in and export a TIFF?

Thanks for any help
Dave

[Michael Rosenberg]

Dave,

I am not sure if you are using the QTR Gui, but you can set gamma in the Gui. For windows I use 1.8, but Mac users use 2.2. You can go to the Yahoo users group and ask that question. You can also open the text QTR profile and set the gray gamma level.

Mike

[DHodson]

Thanks for the response Mike. I'm just getting into this and not very familiar with QTR yet so that's good to know. I'm thinking about the editing I'm doing before I print it out through QTR. I'd like to make sure that I'm working in the same gray gamma that QTR is going to use but so far I haven't found an editing package other than Photoshop that lets me set it. As I mentioned, the folks I spoke with at Corel couldn't tell me what their default is. Maybe I'm missing something though. Does everybody use Photoshop or do they just accept the output from the package they're using?

Regards
Dave

[bob carnie]

Dave I think you should get Photoshop, when you start making more complex negatives down the road this program is tailor made for this application. There is a learning curve but well worth it.


Thanks for the response Mike. I'm just getting into this and not very familiar with QTR yet so that's good to know. I'm thinking about the editing I'm doing before I print it out through QTR. I'd like to make sure that I'm working in the same gray gamma that QTR is going to use but so far I haven't found an editing package other than Photoshop that lets me set it. As I mentioned, the folks I spoke with at Corel couldn't tell me what their default is. Maybe I'm missing something though. Does everybody use Photoshop or do they just accept the output from the package they're using?

Regards
Dave

[DHodson]

Hi Bob

I'm beginning to think you're right. So far it seems Photoshop is the only editing software that lets me select the grayscale gamma. If there is another, nobody has mentioned it.

Thanks
Dave

[The Joker]

PSP doesn't have a working space for greyscale. You can desaturate to grey but I don't think you can use greyscale profiles. I could be wrong about that but If you can't see one then one wasn't supplied. If you can find the profile somewhere else you can just drop it into your profiles folder in the PSP instal directory but I don't think you'll be able to see/use it in PSP.

Windows uses gamma of 2.2

[WalkerBlackwell]

I recommend using Photoshop, Photoshop Elements, or Lightroom for working with Piezography and QuadtoneRIP for various reasons but one being full support for the gamma 2.2 workflow.

Regards,
Walker
R&D of Piezography @ IJM

[Michael Rosenberg]

Dave,

I also recommend getting PS - you can still get version CS6.

Windows was originally designed (default) for gamma 1.8, but it does not matter anymore. What is important is that your workspace/screen calibration match what you set up for PS and QTR.

Mike

[The Joker]

https://msdn.microsoft.com/en-us/library/windows/desktop/jj635732(v=vs.85).aspx#what_is_gamma_and_what_is_it_for_

[Peter De Smidt]

Isn't it the other way around? Didn't Apple used 1.8 for a long time, and Windows was 2.2?

[sanking]

Isn't it the other way around? Didn't Apple used 1.8 for a long time, and Windows was 2.2?

That is the way I remember it!!

Sandy

[DHodson]

You're correct - according to this Cambridge Color article ( http://www.cambridgeincolour.com/tutorials/gamma-correction.htm ) older Macs were 1.8 but not anymore.

Also, the Piezography manual indicates their inks are developed assuming Gamma 2.2 and you can see in the attached image from the manual, that the QTR print tool uses an embedded grayscale Gamma 2.2 (box in bottom right of image)

152004

[The Joker]

From the QTR User guide by "Tom Moore" which comes with QTR.


The .tiff format is very flexible and images stored in this format can have a
wide range of characteristics. Recent versions of QuadToneRIP have
removed many of the constraints on the image characteristics, but it must
be either a grayscale or RGB image. If the image is RGB, QuadToneRIP will
convert it to grayscale. If the image is 16 bit, it will be converted to 8 bit.
Alpha channels in the image will be ignored and layers are permitted. The
image can be in compressed (LZW only) or uncompressed format. Note that
any conversions are only applied to the image data actually processed by
QuadToneRIP. The original file is not changed.


So the need for Corel PSP to be able to use the grayscale 2.2 gamma profile does not exist. QTR handles it.
The standard sRGB profile is a 2.2 gamma profile so with B+W images you should be able to work in that profile, save as tiff and send to QTR which will do its stuff (as I undestand it).

[Sasquatchian]

"The standard sRGB profile is a 2.2 gamma profile"

Not quite. The sRGB profile has a MODIFIED 2.2 gamma tone response curve. It's flattened out at both ends of the tonal spectrum. You can see the difference if you take any neutralized black and white image in a true 2.2 gamma space like Adobe RGB and then ASSIGN sRGB to that. You'll immediately see the change in both highlights and shadows. It's not huge but it's there and for people who are picky and/or exacting, it's a difference that makes a difference.