I've been fiddling around a bit trying to get my web presentations to have a little more of the feel of the original, film-based B&W photographs. Thought I would share these three pix, which I also posted recently to my own web site (http://www.botzilla.com/blog/archives/000147.html)
Anyway, the idea is to find a way to preserve the feeling of the original film/print grain while blowing the pic down to a size that would normally be much, much too small to show grain.
Anyone else struggle with this issue?
Yup, good point. I often notice that compressed, shrunk JPEGs I prepare for online viewing don't really reflect the graininess of the original. JPEG compression can make a photo seem virtually grainless when the original was far from that.
Unfortunately I haven't found a digital grain filter that even approximates the real thing. Sometimes when I want to demonstrate the grain I'll attach a small, 1:1 segment of the original to the JPEG.
What can also help to preserve the appearance of the original grain is to resize the image in steps, tweaking and sharpening it with each resizing.
As mentioned on my journal post (link in original message), the three pix here are:
1. "resize/sharpen cascade" as you describe -- too clean! (good otherwise)
2. "nearest neighbor" resize which loses detail but carries the actual original grain, in terms of statistical sampling -- the effect is to amplify the grain pattern against the overall image.
3. "nearest neighbor" to a larger size, then an additional bicubic downsize, to carry detail and also maintain some of the (amplified, but not as much as before) original grain.
(Curious effect on my old Toshiba laptop -- a subtle purple hue in the first image! Apparently the gray of this laptop screen isn't uniformly gray at all luminance levels... interesting (and makes me glad I've mostly replaced it with a newer laptop))