How does Blending Add/Sub work?

[Twin Matrix]

I have an image with around the edges black and in the center red. I want the black to be displayed and the red to only tint the screen (like "multiply" in Photoshop as layer setting). Or at least just the black.

But when I do "Add" I only see the red, and when I do "Sub" I only see everything slightly tinted.. Or something. At least the center with the red is a bit darker/tinted.

Help appreciated.

Edit: When I invert the image so black > white and red > blue, this is what happens:
"Add": I get white around the borders and blue in the center.
"Sub": I see the black VERY blackish (this is good) and the blue actually became red. O__o Why does this happen only -after- inverting the colors? Is there something wrong? I mean, when it was black/red, it tinted the screen a bit blue, and now it is white/blue it works as black/red.
Also, it's now VERY BLACK. Also in parts where it's black~red or dark red it's just pure black..

I'm trying to get this to work with the proper colors in the picture.. So I don't have to invert all my pictures for them to work. >,<

By the way this is for RMXP.

 

[poccil]

RGSS does not support any other blending modes than add and subtract.  Essentially, the "add" modes adds the intensity of the screen and the intensity of the image; and the "subtract" mode subtracts the intensity of the image from the intensity of the screen.  RGSS does not support a "multiply" blending mode, unfortunately.

 

[Twin Matrix]

Oh, that's a pity. :/ So the only way to get a sort of "multiply" effect is to invert the image's colors and use Sub? o_O''

 

[Unka Josh]

Or script like crazy, of course.

 

[regi]

You can also try separating the image into 2 pictures, one just pure black on "Normal" and the other red pic above on "Add". I'm not sure if that'll work well with your image, though.

 

[Twin Matrix]

^

Well, that could work. But the reason why I'm doing this is because I don't want to work with images that have transparent or semi-transparent pixels due to filesize reasons. So I have to put it on add or sub.

 

[Kraft]

then have the image a lot or a little opaque (see through)
You can do that in it.

 

[Twin Matrix]

^

Hmm, I don't quite understand. Do you mean the opacity of the image? It's not the same everywhere. Like, the original has a black border that fades to the center (so less opacity towards the center). Then behind that black is a semi-transparent red fill. :S BUT, for filesize reasons I have to save it as an indexed png which removes makes transparent pixels > non-transparent, so its a black to red fade image. I thought that if there was a multiply-ish function in RMXP, the black would be really black and the red only a red tint. : D

Now what I ~could~ do is make a black & white image for the black, and only red for the bottom layer of the image and then make the red transparent. Only I'm having issues making just the black appear. X__x Does Sub or Add show black on the map?

By the way this is for RMXP.

 

[Nickster]

a single file here or there that has tranparancies is hardly going to up your file size.

 

[Twin Matrix]

^

Actually, it very much is. And even MORE if I use transparencies in cosmetic fogs.

 

[Kraft]

The Transparency Scroller wheel thingy... use that and the higher the number is (up to 255) the more the image will be see through.  You can do that for images, pictures, fogs, and everything else that you can show up on the map.

 

[Twin Matrix]

Er, opacity 255 = no transparency, and opacity 0 = not visible? Not the higher the number the more you can see through the image? ^^; But then the whole image becomes transparent, which isn't what I want. I think we're kind of straying away from why I originally posted the topic, which was a blending method where the black is black (not transparent) and white doesn't do anything to the pictures behind it (aka. Photoshop multiply). And there's simply no way to do that without using a non-indexed png, for the reason that RMXP's blending methods can't show solid black properly that way (unless you use white in the image, and then Sub.. but then the black looks really jagged o.O).