alright, i can sort of do this one as a script, but it's bulky and just a bit weird that way. paint shop pro has a nice tool called 'hue map'. it's pretty good for adjusting different bands of colors, along with altering saturation and lightness. however, i can find no 'Black and White map' in psp.
in the normal hue map you can simply change a range of colors/hues by adjusting a slider (see attached). the ranges are displayed along the top. what they turn into when you move the slider is displayed along the bottom row.
what i'd like is something similar, but i really only need about 8 ranges (256 divided by 8 = 32). more would be nice, but 8 would be sufficient in most cases.
what i really want to do is to be able to make a selection based on these ranges and 'pick up' that given range in a selection and then be able to modify just that range.
what i currently do with the script is, paste a pre-made image into the image i want to alter. this pasted image is a very small black and white with 8 pre-set grays. these grays are set at the mid points of the multiples of 32. so, one is set at 16*16*16 and the next is 48*48*48 and so on up the line. the script reads the gray values of the pasted image and makes a selection based on that gray. the tolerance to 32 for the selection. the new selection gets pasted into a new layer and an adjustment layer of hue/sat is added into a group for that layer. this is done 8 times using all the grays in the pasted image.
all of that makes for a pretty bulky layer palette, but it does allow me to then adjust each layer for the gray values. i simply open the hue/sat for that layer and change it to what i want as far as brightness in gray. so, this is sort of like 'curves' for gray, but more adjustable (at least to me).
ok, just to keep this honest, i actually dont have the script working right. i can do the selection, layer group, and hue/sat parts ok, but havent worked out how to incorporate two images being handled within the same script, so i manually paste the small gray image into the other first. the point is, the whole thing is rather clumsy. a plugin would be much more elegant, simple to use and visible.
i find it very odd that there are all these color adjustment filters and plugins and very few for b&w's. and that's what i mostly want to do with this plugin, use it on black and whites where you want to change one gray into another, or change many into others. curves also has the disadvantage of going weird when you put a higher value point lower than a lower value point. so, i want something that doesnt rely on a curve system.
and, if this could be a 16 band gray adjuster or even a 32 band, that would be even better.
this shld be possible as a normal .8bf. if it's set up like 'hue map', you wouldnt need to do the 'selections' like i'm currently doing. you'd just call up the plugin and move the sliders and the gray values would change.