ImageMagick Pdf to JPG bad quality - pdf

Question

I am not able to get good color quality from using ImageMagick to convert PDF to images.
MagickReadSettings settings = new MagickReadSettings();
settings.Verbose = true;
settings.Density = new Density(600, 600);
MagickImageCollection images = new MagickImageCollection();
images.Read("C:\\" + Path.GetFileName(fileUrl));
List <string> files = new List<string>();
for (var x = 0; x < images.Count; x++)
{
images[x].Quality = 100;
images[x].BitDepth(24);
images[x].Contrast(true);
images[x].Resize(3675, 2400);
images[x].Write("C:\\websites\\FlyerEditor2\\FlyerEditor\\src\\assets\\" + Path.GetFileNameWithoutExtension(fileUrl) + "-" + (x + 1) + ".jpeg");
files.Add("assets/" + Path.GetFileNameWithoutExtension(fileUrl) + "-" + (x + 1) + ".jpeg");
}
cropped screenshot from pdf
jpg from pdf using imageMagick

Answer 1

if use python3, you can try use wand.
in terminal：
brew install imagemagick#6
pip install wand
in python:
from wand.image import Image
pdf_file = '.../example/a.pdf'
def convert_pdf_to_jpg(file_name, pic_file, resolution=120):
with Image(filename=file_name, resolution=resolution) as img:
print('pages = ', len(img.sequence))
with img.convert('jpeg') as converted:
converted.save(filename=pic_file)

Answer 2

I found major differences in imagemagick's convert handling of colorspace between Linux and Windows.
Using commands
convert -density 300 -colorspace RGB my.pdf my.jpg
convert -density 300 -colorspace sRGB my.pdf my.jpg
On Linux, both -colorspace sRGB and -colorspace RGB generated images where contrast and palette were a major diversion from the original, contrast was increased and colors were a far match from the original.
On Windows, both -colorspace sRGB and -colorspace RGB were acceptable if not perfect.

Answer 3

Ok the issue has nothing to do with imageMagick. It is a simple issue with color pallets. Converting a pdf to a jpeg by default uses cmyk, while the web standard is RGB