How to set a pixel grid to real life dimensions?
Printed From: Pixel Joint
Category: The Lounge
Forum Name: Resources and Support
Forum Discription: Help your fellow pixel artists out with links to good tutorials, other forums, software, fonts, etc. Bugs and support issues should go here as well.
URL: https://pixeljoint.com/forum/forum_posts.asp?TID=21817
Printed Date: 14 September 2025 at 12:08am
Topic: How to set a pixel grid to real life dimensions?
Posted By: SegaGenesis
Subject: How to set a pixel grid to real life dimensions?
Date Posted: 12 March 2015 at 7:37pm
| I am currently using the program GraphicsGale but I have just started using it. I would like to set the grid so that each pixel/square matches the real life measurements for what I want it to be. For example if I am doing a real life project where I need it to be 8x10 with each pixel/square in the grid being half an inch how would I go about setting the grid to those dimension? I would like to know so I can see 1- What the finish product will look like when I make something in real life measurements. And also how many of the squares I will need. If you can help I really would appreciate it! |
Replies:
Posted By: neota
Date Posted: 12 March 2015 at 11:44pm
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You need to find out the PPI of your screen. For example, the PPI of my screen is 90, meaning that there are 90 pixels to an inch (at 100% zoom. 45 at 200% zoom, 30 at 300% zoom, etc). This is all the info you need to construct a grid. In other programs, like Photoshop or GIMP, you can modify the PPI directly, to control the print/display size. For example, by setting PPI to 1, you are saying that each pixel in your image should cover an inch on screen or in print. By setting it to two, that would be saying that each pixel should equal a half inch. ------------- absolutely. |
Posted By: SegaGenesis
Date Posted: 13 March 2015 at 1:57pm
| Thanks for your help. I am still a little confused. I hope I have it right. With gimp I am currently working on a 16 bit image. So I made a new image and made the height 16 and the width 16 in pixels. Then I clicked image and selected scale image. If I wanted to try it 1 inch per pixel I select 1.000 for the X and Y resolution and make sure pixels/inches is selected then? Is this correct? Also if I copied and pasted an image after setting up these guidelines would it break it down so 1 pixel equals 1 inch again or would I have to rescale it? Thanks again for any help. |
Posted By: yrizoud
Date Posted: 13 March 2015 at 3:07pm
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Originally posted by SegaGenesis I am currently working on a 16 bit image. So I made a new image and made the height 16 and the width 16 in pixels. I think you're mistaken. The Super Nintendo / Super NES is one console of the "16-bit" era, but this number refers to the processing power of its microprocessor, and doesn't translate to its graphic capabilities. It's much more relevant to consider : 1) That the image that this console sends to TV (fullscreen) is 256x224 pixels.  It's a good idea to always draw on an image of this size, because it's easier for you to see how much detail you can put into something, and how much space it occupies on a screen. 2) memory is scarce and it's more efficient to draw stuff in multiples of 16x16 pixels, so sceneries are very often drawn by re-using tiles of 16x16 pixels. See for examples the trees above, the same 2x2 blocks are repeated 3 times. 3) palette precision has only 32 degrees of detail for R G B channels. To mimic it on a program which lets you edit colors from 0-0-0 to 255-255-255, you should restrict yourself to numbers 0, 8, 16, 32, ... 240, 248, 255. 4) The total number of colors is limited. The specific limits are quite complicated, but as a general guide, to mimic the style you should re-use similar colors instead of creating new colors every time you draw something. |
Posted By: SegaGenesis
Date Posted: 13 March 2015 at 4:30pm
| Thanks for your help. Yeah, I am pretty new to this so I am probably confused. I appreciate your heads up on drawing things to the specific measurements of a full screen shot. Is it possible though if I find a sprite from a 16 bit video game. I then copy and paste that image to gimp or GraphicsGale. Could it then be scaled so that each pixel will represent a half of an inch ? So that if I wanted to create something with it I would know what it would look like and what size it would be in real life? I can't figure that part out. Sorry for being such a beginner lol. |
Posted By: neota
Date Posted: 13 March 2015 at 6:00pm
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I can't comment on whether GGale has a PPI option, but in GIMP, you can indeed use Scale Image to adjust the PPI ('resolution') to 2. You should then make sure that 'View->Dot for Dot' is unchecked. (When Dot for Dot is checked, the PPI settings are not used in displaying the image, whereas if it is unchecked, they are used.) There is also an option 'Use "dot for dot" by default' in Preferences -> Image Windows. If you turn this off, then all image windows will use PPI settings for displaying the images by default. Note that the behaviour of PPI is dependent on whether GIMP has the right idea of what your monitor's PPI is. So I recommend measuring the result to verify that 1 image pixel is actually occupying one inch. If it isn't, then you'll need to fix that. The Display section in GIMP preferences allows you to manually override the PPI values that the OS is providing. You can do that by taking your monitor's resolution, measuring the physical size of your display area in inches, and dividing the first by the second. For example, my display area is about 18.75" by 11.9", and resolution is 1680x1050. That gives a X PPI of 1680/18.75 == 90, and Y PPI of 1050/11.9 = 88. HTH. ------------- absolutely. |
Posted By: yrizoud
Date Posted: 13 March 2015 at 6:14pm
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I don't understand why you'd want to zoom so much, as on a typical screen you'd see barely more than a pot from the above image. The above screenshot, displayed in real life at 2 Pixels Per Inch (PPI) would occupy 128 inch * 112 inch (3.25m * 2.84m) |
Posted By: neota
Date Posted: 13 March 2015 at 6:34pm
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I assumed it was for some kind of textile. Personally I'd agree that there isn't any particular advantage to making pixels ridiculously huge, but I suppose if you need to visually match it up with a physical object (like a pre-existing physical piece of art), there might be some justification for it. ------------- absolutely. |