Legacy ImageMagick Discussions Archive

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convert in.png -colorspace srgb -type truecolor out.tif

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$img = new Imagick();
$img->readImage('in.png');
$img->transformImageColorspace(\Imagick::COLORSPACE_RGB);
$img->setImageType(\Imagick::IMGTYPE_TRUECOLOR);
$img->setImageFormat('tiff');
// there's a reason I am using file_put_contents, not writeImage(), but assume it has no impact with this issue.
file_put_contents('out.tif', $img);

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$img->setoption("colorspace:auto-grayscale", "off");

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convert in.png -colorspace srgb -type TrueColorAlpha out.tif

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#!/bin/bash
############################################
# convertGreyscaleTosRGB
# Transform images from "Gray" to "sRGB" colourspace
# Created by: sir8472
# Created on: 2018/12
#
# Take an image and check to see if it's "Grey" colourspace, if so convert it to "sRGB" overwriting the original file.
#
# Notes
# -> Imagick sRGB is used instead of RGB for preservation of transparency
# -> The script has been tested on ubuntu 16.04 and 18.04
# -> file names with special characters cause problems. I don't have any of these, but you may need to edit to fix for your use case
# -> use at your own risk!


# Running the script
# ./convertGreyscaleTosRGB.sh -f /path/to/my/file
#
# Alternative: use find to pass in lots of files.
# find /path/to/images -iname "*.tif" -exec /path/to/script/convertGreyscaleTosRGB.sh -f {} \;
############################################

# I want images to end up in this colourspace
TARGET_COLOURSPACE="sRGB"

# If we have no flags passed, exit
if [ $# -le 0 ]; then
    echo "No arguments found, can't continue!"
    exit
fi

# Match the flags to functions (I assume I am adding some more later)
while [ "$1" != "" ]; do
    case $1 in
        -f | --file )           shift
                                filename=$1
                                ;;
        * )                     echo "nope, no idea what you want. Quitting"
                                exit 1
    esac
    shift
done

# for the provided image, check to see what colourspace it is.
file_colourspace=$(identify -format '%[colorspace]' $filename)

# If the current colourspace doesn't match the desired colourspace, convert it
if [ "$TARGET_COLOURSPACE" != "$file_colourspace" ]; then

    convert $filename -colorspace srgb -type TrueColorAlpha $filename

    # get the new colourspace
    new_file_colourspace=$(identify -format '%[colorspace]' $filename)

    # Record it in a log
    echo "$filename was $file_colourspace and is now $new_file_colourspace" >> converter_changed_files.log

    # Output it to the screen too
    echo "$filename was $file_colourspace and is now $new_file_colourspace"
else
    # if it isn't a match, log it to ignored files log, incase I need to review unexpected failures later
    echo "$filename is $file_colourspace" >> converter_ignored_files.log
fi

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$img = new Imagick();
$img->readImage('in.png');

// Convert the image to a TIF file
$img->setImageFormat('tiff');

// Set the image type to TrueColour Matte (transparency should be preserved)
// SEE: 
// https://github.com/mkoppanen/imagick/issues/109
// https://stackoverflow.com/questions/34220981/setting-color-depth-with-imagick
// http://php.net/manual/en/imagick.constants.php
$img->setType(\Imagick::IMGTYPE_TRUECOLORMATTE);

$img->transformImageColorspace(\Imagick::COLORSPACE_sRGB);

// This works fine...
// file_put_contents('out.tif', $img);
// but as per snibgo's comments you should use this:
$img->writeImage('out.tif');