Composit multiply gives low quality picture output

[myoglu]

Hi!
This is the command Im using:

composite -compress none -compose Multiply -gravity Center x.tiff Grid-resized-green.tiff out.tiff

The file "Grid-resized-green.tiff" is uncompressed and of high quality, so I can see all pixels as pure green when I zoom in.
The "out.tiff" is both these pictures "merged", BUT now the the pixels from "Grid-resized-green.tiff" is NOT pure green.. Its lighter/darker etc. corresponding to the background picture (x.tiff).

How to fix this, I dont want a lot of different varieties of green, I want PURE green, only one type of green.

Thanks!

[snibgo]

I don't know what "only one type of green" means.

Can you post your input and output files somewhere like dropbox.com and paste the URLs here.

[myoglu]

https://www.dropbox.com/sh/gvskkg4gnxvg7hk/eMQYV8mAYI

Does the link work?

One file, with white background is "the correct one". The other is how it looks when merged... Different varieties of green..

[snibgo]

And your input images?

[myoglu]

Uploaded now "TVxx.tif" and "grid.tiff"

Thanks!

[snibgo]

I prefer to use convert rather than composite. In Windows, the equivalent of your command ...

Code: Select all

convert ^
  Tv290.tif ^
  grid.tiff ^
  -depth 16 ^
  -gravity Center ^
  -compose Multiply -composite ^
  out.tiff

... does exactly what I would expect, multiplying the pixels. Where the grid is white, the output is the same as tv290. Where the grid is green, green is multiplied by the tv290 pixel, and the result is different to both.

Note that grid.tiff has two different shades of green. Where lines intersect, the pixel is darker.

I don't know why you are multiplying.

I think (but I'm not sure) that you want to overlay the green pixels over tv290. I'll make the white grid pixels transparent, then place the grid over tv290.

Code: Select all

convert ^
  Tv290.tif ^
  ( grid.tiff -transparent White -write g.png ) ^
  -depth 16 ^
  -gravity Center ^
  -compose Over -composite ^
  out2.tiff

The two shades of green are copied unchanged.

[myoglu]

THANK YOU SO MUCH!

That is perfect.