First what I wanted; 16 bit greyscale images, Gamma 2.2, from scanned 6x6 and 6x9 BW negatives as keepers and either saved Qimage selective color or curve settings as filters on the image to get sepia, half-sepia, bronze, etc toned images. So I do not have to keep more images stored.
The saved selective color setting or curve does not work on an 8bit or 16 bit greyscale image that has Gamma 2.2, 1.8 or DotGain10 and probably any other greyscale space assigned, it works when the file is unassigned. With neutral 8-16 bit RGB files, either assigned or unassigned, all works.

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Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.

Mike,

16 bit greyscale Tiffs saved from Photoshop 5.5. The most recent Qimage Ultimate running on Vista. I experienced it first with big files and tried it with a small file in 6 varieties saved from Photoshop, the Gamma 2.2 etc assigned greyscale Tiffs do not show the color shift in the preview of the selective color tool (sepia) and do not get the color either with OK, same for a curve I made (bronze). After your message I tried it with some Jpegs, same results. Restarted Vista and Qimage Ultimate, same results. There is short sepia flash in the image when I press the OK button but it falls back to the neutral greyscale image right away. Like written before there are no issues with unassigned greyscale images and no issues with RGB images. The images I used are from different sources, scanned greyscale and greyscale target images you can find on the web.

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Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.

Sounds logical if it stretched to Unassigned Greyscale images too, it does not however. I can give a color cast like sepia to Unassigned Greyscale images anywhere in Qimage; curves, selective color, global filter, print filter and it will give me a color toned image with print to file and a color toned print through my printer. The soft proof even shows the color tone as well if filters like that are used on an Unassigned Greyscale image. The preview, edit window and resulting thumbs show it when an Unassigned Greyscale image gets the sepia color tone treatment in either the image editor's selective color or curves tool.

If I had observed that Unassigned Greyscale images behaved the same as Assigned Greyscale images I would not have written the first message. I would have thought a pity that it is not implanted in Qimage while it is possible but at least there would be some logic in that decision.

My recollection is that a Greyscale image is made RGB in Qimage's route to the printer. It looks like that happens in an early state with Unassigned Greyscale images too as they can get a color cast in Qimage but is suppressed on Assigned Greyscale images for unsure reasons hence the color cast flash when the selective color is given the OK in the image editor. An Unassigned image whether Greyscale or RGB is most likely the same for Qimage from a very early state on, let us say from the creation of the thumbs it is seen as RGB. That is fine for me.

If Qimage keeps it promise of non destructive editing on images it would be nice if Greyscale originals (scanned B&W film or digital monochromes) fall within that category. The advantage of storing a smaller size with Greyscale compared to neutral RGB images exists and Qimage is able to make neutral RGB of a Greyscale image. If my observations lead to similar measures taken on Unassigned  Greyscale images that happen on Assigned ones then that is counterproductive for me but logical in your way of thinking. There is another option.

An Unassigned Greyscale image and a Gamma2.2 Assigned Greyscale image are given resp. sRGB and Gamma2.2 space profiles in the print queue. Make the last AdobeRGB  when a Gamma2.2 is present and let it behave accordingly in the rest of the software. sRGB is less nice as its gamma is not strict 2.2. Greyscale Gammas usually have a suitable RGB color space with the same gamma to translate to, the smaller gamut ones are preferred in this case of greyscale conversions and possible color toning. So Colormatch instead of ProPhoto for Gamma 1.8.

Edit: In color management the General ICC Profile Embedding Options > Extract EXIF Model could get an extra choice to extract Gamma 2.2 etc from a B&W image and have AdobeRGB assigned to that file then. The default sRGB for unassigned images could still work as usual for both unassigned RGB and Greyscale files.

It could be that you made that distinction on Ass and Unass Greyscale images in the past when the QTR B&W printer profiles showed compatibility issues in Qimage. Just a guess. There is still that choice to use the RGB variant of the QTR B&W printer profiles. The normal color printer profiles are no problem at all.


--
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.

The unasigned color space is precisely the reason it works with an unassigned space.  When you open an image that has no image color space, sRGB is assigned as default.  By you assigning a grayscale color profile, you've made the image color space grayscale: that color space literally has no color component.  Same thing happens in PhotoShop or any other program.  If you try to add color to a grayscale image, you get a message that you must first convert out of grayscale mode and go into a color editing mode.  So do the same thing here: take the image, put it in the queue, choose "Convert Images" and convert using a profile-to-profile conversion: from <input> to Adobe RGB, or sRGB, or some color space that allows color.  But you need a color editing space to be able to do color work.  And that's true no matter what the software.

Mike

It's actually only 1.5 times the size.  You're already using 2 bytes per pixel with that 16 bit grayscale image.  An RGB save would only be 3 bytes/pixel.

And with hard drive cost down to about $40 per terabyte, you could probably do a few. 

Technically QU should warn or prevent you from doing anything that adds color in the editor if the image is in a gray color space.  I may do something with that down the road, just so people don't wonder why they can't get color from an image if it's a grayscale image in a grayscale color space.

Mike