Say I am designing a 3000*3000px image. It's only going to be used on a black shirt with a 10*10in printable area.

If I want to emulate transparency gradients, can I convert, say, a grayscale image to bitmap (so it only has black and white), then change the black to transparent, save as a png, and use it? The image only contains white, but if viewed on a black background, it looks like a gradient (or grayscale) because of the varying density of white pixels.

Here's an example of what this kind of image would look like if it were on a black background (and extremely zoomed in, if you take each square to be a pixel):
http://www.webwasp.co.uk/defin...zoom-black-White.gif

Will the fact that there are some 1px*1px (or 2*2px or 10*10px...) white areas be a problem?

Basically, is there a minimum sized area that can be white? (this would be in inches). If yes, what happens if I try to use the kind of image I've described? Would I get blobs if the tiny white areas are near each other? Or would the parts that are supposed to be 1px (~1/300th of an inch) just be left off?

I realize that 1/300th of an inch is a little silly anyway... but what about 1/64th or 1/128th?

Thanks!

*EDIT for clarification --
I originally wrote: "If I want to emulate transparency,"
But I meant: "If I want to emulate transparency gradients,"

This message has been edited. Last edited by: existant,

If you use greyscale as any part of your image production process be sure to go back to RGB mode before uploading.

You can't "change black to transparent" - or change any color to transparent and get good results. The "treat color x as transparent" process uses indexed transparency. Indexed transparency won't stay transparent on CP. GIF images use indexed transparency, so does PNG8. You need alpha transparency, PNG-24 or PNG-32. To print transparent on dark you MUST use PNG-24 or PNG-32. Gif will not work. PNG-8 wil not work. http://www.tutortanith.com/designtips2.htm

quote:

Will the fact that there are some 1px*1px (or 2*2px or 10*10px...) white areas be a problem?

If you have white in the image then you can expect to see white in the final product. If it is a tiny bit of white then you can expect to see, possibly, MORE white. You won't see less, it will NOT be "left off." The way I learned to check my images for almost but not quite transparent pixels was getting a shirt with white flecks. I checked the image and sure enough. Although not easily visible there were indeed a few scattered bits of pixels with faint color.

Thanks for the info about the white 'flecks.' That's good news for me since that's the effect I'm trying to acheive.

Hopefully the method I used to format the image worked. I did use indexed transparency to get the effect that I wanted, but then I converted the image back to RGB and saved it as a (32 bit) PNG. So I guess we'll see.

Thanks!