Identify verbose can't detect alpha channel

[markzman]

Hello everyone,

I've just installed the 6.6 version of imagemagick and noticed that when i execute the verbose command it doesn't detect anymore the alpha channel even using the -format %A parameter it returns a false statement. see below verbose output of a test image with alpha channel.

Image: test_alpha.tif
Format: TIFF (Tagged Image File Format)
Class: DirectClass
Geometry: 1102x864+0+0
Resolution: 188.88x188.88
Print size: 5.83439x4.57433
Units: PixelsPerInch
Type: TrueColor
Base type: TrueColor
Endianess: MSB
Colorspace: RGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
Channel statistics:
Red:
min: 0 (0)
max: 65279 (1)
mean: 153.784 (0.603073)
standard deviation: 50.7549 (0.199039)
kurtosis: 0.153505
skewness: -0.288556
Green:
min: 0 (0)
max: 65279 (1)
mean: 149.425 (0.585982)
standard deviation: 56.0807 (0.219924)
kurtosis: -0.662065
skewness: -0.108865
Blue:
min: 0 (0)
max: 65279 (1)
mean: 104.951 (0.411574)
standard deviation: 76.5669 (0.300262)
kurtosis: -0.900334
skewness: 0.838951
Image statistics:
Overall:
min: 0 (0)
max: 65279 (1)
mean: 102.04 (0.400157)
standard deviation: 82.0473 (0.321754)
kurtosis: -1.26869
skewness: 0.181201
Rendering intent: Undefined

[magick]

The problem may be specific to your image (we're getting alpha channel statistics for our images). Post a URL to your image so we can download and inspect it.

[markzman]

here it is..
http://www.clipartof.com/images/free_ho ... alpha.tiff

im using Imagemagick 6.6.0 Q16 on Windows XP SP2

[markzman]

Hello magick any news on this?

[magick]

The problem is fixed. We'll get a new point release out within the next few days.

[markzman]

additional concern on the same test image above regarding removing the alpha channel some pixels from the rgb channel were also removed i'm not sure though if i have the correct syntax

syntax:
convert test_alpha.tiff -background white -flatten +matte test_alpha_removed.tiff

here's the output:
http://www.clipartof.com/images/free_ho ... moved.tiff

and the screenshot comparison:
http://www.clipartof.com/images/free_ho ... enshot.jpg

[magick]

ImageMagick is behaving properly. The -flatten option blends the background color with the image with the Over composite operator. Perhaps Photoshop is using a different blend operator.

[markzman]

version 6.6.0-3 resolves alpha detection issue thanks magick appreciate the help!

as for the removal of alpha channel i figure i should have only used +matte instead of adding -flatten to avoid blending problems.

[markzman]

Would it be possible to detect alpha channel on grayscale images?