Legacy ImageMagick Discussions Archive

Hi,

I have a tiff file in phososhop with 4 channels (RGBA), once it's converted all the channels are mixed and I can only see 3 channels (RGB and A is gone).

I tried different options and even the one that is supposed to force alpha still doesn't work:

ImageMagick-6.7.8-6\convert.exe test-alpha.tif -resize 512x512 -type TrueColorMatte -alpha On alpha-512.tif
ImageMagick-6.7.8-6\convert.exe test-alpha.tif -resize 128x128 alpha-128.tif

Here's the original and converted image: http://narod.ru/disk/57731551001.6bb800 ... k.zip.html



Could you please give any hints? thanks!



I provided a bit more info here: https://www.imagemagick.org/discourse-s ... 052#p88052

Sorry, all I can say is that when I tried it on my Mac in IM 6.7.8.6 Q16, the alpha channel was in the output image as seen in PS CS. Sorry I only have that old version.

Perhaps some other windows user with PS can test your command and image.

Can you please try opening the attached image in your PS version. It would be great if you could tell me whether it shows an alpha channel in it on your computer and PS version.
Thanks!

IM 6.7.8.6 Q16 Mac OSX Snow Leopard


identify -verbose test-alpha.tif
Image: test-alpha.tif
Format: TIFF (Tagged Image File Format)
Class: DirectClass
Geometry: 256x256+0+0
Resolution: 72x72
Print size: 3.55556x3.55556
Units: PixelsPerInch
Type: PaletteAlpha
Base type: TrueColor
Endianess: MSB
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
alpha: 8-bit
Channel statistics:
Red:
min: 0 (0)
max: 128 (0.501961)
mean: 24.6875 (0.0968137)
standard deviation: 50.5027 (0.19805)
kurtosis: 0.42377
skewness: 1.55685
Green:
min: 0 (0)
max: 128 (0.501961)
mean: 24.6875 (0.0968137)
standard deviation: 50.5027 (0.19805)
kurtosis: 0.42377
skewness: 1.55685
Blue:
min: 0 (0)
max: 128 (0.501961)
mean: 24.6875 (0.0968137)
standard deviation: 50.5027 (0.19805)
kurtosis: 0.42377
skewness: 1.55685
Alpha:
min: 0 (0)
max: 128 (0.501961)
mean: 105.167 (0.412419)
standard deviation: 48.7059 (0.191004)
kurtosis: 0.865592
skewness: 1.68868


In PS CS I see an alpha channel.




identify -verbose alpha-128.tif
Image: alpha-128.tif
Format: TIFF (Tagged Image File Format)
Class: DirectClass
Geometry: 128x128+0+0
Resolution: 72x72
Print size: 1.77778x1.77778
Units: PixelsPerInch
Type: PaletteAlpha
Base type: TrueColor
Endianess: MSB
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
alpha: 8-bit
Channel statistics:
Red:
min: 0 (0)
max: 129 (0.505882)
mean: 5.35071 (0.0209832)
standard deviation: 25.1982 (0.0988164)
kurtosis: 19.0631
skewness: 4.58056
Green:
min: 0 (0)
max: 129 (0.505882)
mean: 5.35071 (0.0209832)
standard deviation: 25.1982 (0.0988164)
kurtosis: 19.0631
skewness: 4.58056
Blue:
min: 0 (0)
max: 129 (0.505882)
mean: 5.35071 (0.0209832)
standard deviation: 25.1982 (0.0988164)
kurtosis: 19.0631
skewness: 4.58056
Alpha:
min: 0 (0)
max: 130 (0.509804)
mean: 105.193 (0.412522)
standard deviation: 48.0785 (0.188543)
kurtosis: 0.875744
skewness: 1.68248


In PS CS, I also see an alpha channel.