TIFF/PNG Alpha channel

[dankoz51]

Is there any way to preserve TIFF alpha channel information upon conversion to png, or maybe convert at TIFF and be able to have it specify the transparent color, choose the lightest or otherwise be able to convert directly from tiff to png without having to convert to something else first.

I have a several tiff files that need conversion its an image with a white background. I would like to make the white transparent and have tried several of these to no avail.

nconvert -out png -q 100 -o i1.png -resize 250 250 -ratio -transpcolor 255 255 255 -rflag decr -dpi 72 -text_flag bottom-center -text_font arial 24 -text_color 55 255 99 -text "Issue x" -overwrite issue1.tif

I have also tried -tranparent (0, 255 and a few others), -merge_alpha and -add_alpha (0 makes the whole image transparent, other seem to have no affect).

Anyone with any ideas?

[xnview]

by default alpha channel is kept. So could you send me a tiff sample?

[dankoz51]

Sent if to you via email.