11-18-2020, 12:32 PM
Quote:...I have two transparent background files sent to me by my friend that were made in PS. One is 4.3M and at 900x1200 pix. The other is 4.5M and at 2700x3600 pix.
The image size is no real indicator of file size. I have a PS psd template that is 2400 x 1700 pix with a file size of 28 MB but it also has 21 layers, some with a mask, each adding to the file size.
Quote:...I would like to get the best possible resolution file that I can make available for download on a site
so people can use it to print t-shirts and other wares...
Your intent is files for printing on goods. Tee-shirts, coffee cups maybe. You need to consider the image content.
Photographs use jpeg. This is a lossy 'final' format with good compression, does not support transparency. Work in Gimp xcf until that final 'export'. You can also use png as a final format. Png has lossless compression, it does support transparency (alpha channel adds to the image size)
Logos, bold designs etc. You can use png for these although truthfully logos are best made as vector images with Inkscape.
Using tiff, this format is really a wrapper, more variations than enough, from fax images to scientific imaging. It has some use in Gimp in conjunction with the DP program Scribus. Probably not the best format for your intended use.
Quote:...I have made a few transparent background versions: 900x1200 trans.png 393k
900x1200 trans.pdf 312k (shows with white background in viewer)
A PDF does not support transparency. As the name says, Portable Document. Think printed on paper.
Which leads to the printing process. There is no white ink. The printer uses primary colours Cyan, Magenta, Yellow + Black. White is whatever the colour of the paper / fabric / ceramic. When white is required in the image it is has to be specified, then becomes a custom job for the printing company and (much) more expensive.
Quote:...I also understand that .pdf's are a preferred file type because it's a vector file..
Not really true. Only for logos and simple designs, and these are best made with Inkscape or other vector editor, Even these can contain a raster image or a mix. This example, https://i.imgur.com/bB8tCOl.jpg two pdf's basically the same logo, All vector in inkscape, all raster from Gimp. For printing at the set size, 4" x 4" no difference in quality, big difference in file size. Start changing the size then a vector image (scaleable .svg or PS .ai) is preferable.
Advice:
Get to know the relationship between image size in pixels / printing resolution and printing size see: https://www.gimp-forum.net/Thread-Image-size-in-Gimp
If you are going to send your images off for printing on a tee-shirt, then find out the size requirements. A maximum size of say, 12" gives you an image size in Gimp of 12 X 12 (inches) x 300 pixels-per-inch (ppi) = 3600 pix x 3600 pix.
A coffee cup might be 3" x 6" @ 300 ppi = 900 pix x 1800 pix. No good sending the same image for both.
Image format: Back to jpeg for photographs and png for others. PDF if you must.