Glass, 50-70% gray fill + Photograv3

[Zsolt Paul]

I am testing today to find the best combination of gray fill and dithering for glass. I am trying to compare photoshop and photograv. I am filling a simple strip with 50% and 70% gray instead of solid black to space out the spots and get a more frosted look on the glass.

Photoshop will just dither the fill as epxected with dots. However, when I bring the 8 bit gray filled image into photograv3 and choose the glass param, in the interative mode I can see that photograv reset the gray scale for both black and white to 76. This produces a solid black once again (or solid white depending on how you look at it, but you know what I mean..). When I manually pull the slider all the way left and right (black 0 and white 255) then the dithering appears, but it looks like fewer and bigger dots than what photoshop produces for the same gray scale. Playing with the sliders will produce different amount of dots and patters, but the patterns look very "mechanical", not what I am used to for Photograv. It is supposed to excell over photoshop in the dithering pattern, that's kind of the point as I look at it.

If I process the file in photograv according to the default glass settings, it produces a file WITHOUT dithering!! Either a solid black, or solid white (depending on the invert setting), yet it was imported as a 50 or 70% gray.
Why is photograv making my grayscale to one solid shade again as the default param is set? Does anyone have experience with using photograv for 50 or 70 % gray fill?

Thanks!

[Zsolt Paul]

Update: I was only testing a box filled with a single color gray, that's why photograv put both black and white sliders to 76. When you use a file with multiple shadings, the black slider will show the darkest and the white slider the lightest gray shade there is in the file. DUH!!!! However, what this does is pretty much ignores your (my) INTENTIONAL drop from 100% black to 70 or w/e % one choses. It looks at the file as if my 50 or 70% gray was the black and the the white was w/e the white was. If one wants to use photograv and maintain the lower gray shading, one has to manually slide sliders to extreme left and right. The dithering its doing I am still not crazy about though....

[Steven Wallace]

I applaud your efforts... it seems that we are always more critical of our work than our customers are.

[Zsolt Paul]

Thanks and very true!