01-08-2020, 05:11 PM
It's hard because you don't know the basics. You are doing the equivalent of building a chair by gluing matches/toothpicks, and then
try to make the chair big enough to sit on it.
Gimp works in pixels, and its these pixels that give details to the image. If you stretch the image to more pixels, the resulting image doesn't contain more information. The original pixels are just spread of several pixels, so either you see big squares as in pixel-art (no interpolation), or you get something blurry (with interpolation).
The correspondence between inches and pixels is called the "print definition", expressed in pixels per inch (or abusively in dots per inch). In Gimp, see "Image>Print size". This is what sets the ruler in inches. But don't jump with joy, there is a catch, expressed with a formula:
print size in inches = image size in pixels / print definition in PPI
In other words, these three values are interrelated. For a given size in pixels, if you change the print definition to change the print size. But for a nice a crisp print the print defitnion should be more than 150PPI, ideally 300 or more.
In other words, if you want a decent image, you have to know in advance at what size and minimum definition you want to print it, and start te image in Gimp with an adequate size in pixels. The "advanced options" in the "File>New" dialog let you specify an image in inches and PPI, and will compute the required pixels. But of course if you take a random image on the web, it may no be big enough. For your 40"x22" board, you would need at least a 6000x3300px image (150PPI) and double this for 300PPI (12000x6600).
One last catch: the image on your screen is displayed with your screen resolution by default, and since your screen often has a lower resolution that a print, the image will appear bigger. To vie the image at its true size, reset "View>Dot for Dot" and make sure that Gimp uses the proper definition for your screen.
You will note that most of the notions above have nothing to do with Gimp per se, you would have the same problems with Photoshop or Paint, that provide tools equivalent to Gimp's to address them.
try to make the chair big enough to sit on it.
Gimp works in pixels, and its these pixels that give details to the image. If you stretch the image to more pixels, the resulting image doesn't contain more information. The original pixels are just spread of several pixels, so either you see big squares as in pixel-art (no interpolation), or you get something blurry (with interpolation).
The correspondence between inches and pixels is called the "print definition", expressed in pixels per inch (or abusively in dots per inch). In Gimp, see "Image>Print size". This is what sets the ruler in inches. But don't jump with joy, there is a catch, expressed with a formula:
print size in inches = image size in pixels / print definition in PPI
In other words, these three values are interrelated. For a given size in pixels, if you change the print definition to change the print size. But for a nice a crisp print the print defitnion should be more than 150PPI, ideally 300 or more.
In other words, if you want a decent image, you have to know in advance at what size and minimum definition you want to print it, and start te image in Gimp with an adequate size in pixels. The "advanced options" in the "File>New" dialog let you specify an image in inches and PPI, and will compute the required pixels. But of course if you take a random image on the web, it may no be big enough. For your 40"x22" board, you would need at least a 6000x3300px image (150PPI) and double this for 300PPI (12000x6600).
One last catch: the image on your screen is displayed with your screen resolution by default, and since your screen often has a lower resolution that a print, the image will appear bigger. To vie the image at its true size, reset "View>Dot for Dot" and make sure that Gimp uses the proper definition for your screen.
You will note that most of the notions above have nothing to do with Gimp per se, you would have the same problems with Photoshop or Paint, that provide tools equivalent to Gimp's to address them.