GIMP Version: 2.8.10
Operating System: Windows
GIMP Experience: Beginner Level

---

Hello, everyone,
I`ve been spending the last 3 days trying to figure out what I`m doing wrong. I`m prepping a decal sheet for my RC car project with images that have each been properly scaled down (they print out the right size, even if I didn`t paste them to a blank A4/US letter template). It`s when I consecutively copy/paste them to a new blank template, they all shrink. I've bought some very expensive glossy self-adhesive film for my inkjet, so I'm trying to place all my decal logos on the same sheet, so as not to waste this film from England. Any ideas of what I may be doing wrong? I'm getting frustrated, after 3 tries (each a 12hr+ day!!).
Help!!
Thank-you for any tips/ ideas that can help me finish my vacation project!
S

Why do you need to consecutively copy/paste them to a new blank template/canvas? Can't you use the image that you say prints out correctly, without all the coping/pasting?

I may have not been well understood, so here goes:
1)I've D/L jpeg images/logos
2)I've rescaled them directly to desired size, without pasting them to a blank page first
3)Saved the rescaled image to disk
4)Now, with a new A4 blank, attempting to put all my rescales together on one sheet, to create one decal sheet for my RC car

It's at step 4 that when I have finished placing all my decals, and I test-print to see if all's well, it's when I discover that all my decal jpegs are smaller. On the second day, I scrapped the previous project, copied/pasted once again to a new A4 blank, and even rescaled each decal to what its supposed to be (once printed), before pasting next decal image, rescale, and so on. The images I d/l are usually as large as I can find, for best definition, and then reduce them to desired size.

So, to answer your question, I do not want to waste a self-adhesive A4 sheet (@ 4$CAN/sheet) just to print a decal the size of a dime or a quarter on it.

Hope this clears up my question for you
Thanks again
S

I'm not sure if this will be of any help to you, but have a look...
http://gimpforums.com/thread-a4-size-on-gimp

Have you tried not using the A4 template and just creating a canvas of 8.5 inch by 11 inch (about 21.5 cm by 27.9 cm) and seeing if this works, before any printing is done on the expensive film.

What about checking the resolution between the decal images and the a4 settings? AFAIK, A4 is automatically set to 300 ppi, while making an 8.5 x 11 allows you to set the resolution to what you want.

There is a print definition in the templates, but for all image the print definition can be changed. Actually for Gimp 8.5x11 is meaningless if it doesn't come with a print definition (otherwise Gimp cannot compute the necessary size in pixels).

What do you mean by "shrink"? If you copy an area 200 by 300 pixels, it is smaller that 200 by 300 in the copy?

Or the printed image is smaller than you expect?

Ok, maybe I'm not so clear, so here goes:
1)d/l a jpeg 2362x337 pixels@300dpi, saved it to disk (BTW, I'm using them in millimeter units 199.8x27.9mm, to be able to use my rulers on the RC body);
2)rescaled it to 1474.5x208.5px (not sure the dpi changes?) or 124.7x17.7mm in my metric world (the actual size I need)
3)simply printing the rescale gives me exactly what I need on a 8.5x11 test sheet, but when I...
4)copy/paste to a blank A4 (the actual worksheet size I'm to print to), then print out a test sheet, it has been reduced by about 12-13%. Also, the same original jpeg was also rescaled to 1169x167px (98.9x13.5mm), then copied/pasted to same A4 sheet, and somehow got reduced to about 95% of its wanted size once test printed (huh?).

As you can see, the problem lies at the point I attempt to simply copy/paste rescaled decal logo to a unified sheet, to create a single sheet with all my rescaled logos (28 decals in all, of various sizes, originating from about 10-11 original jpegs).
Am I setting something up wrong? (remember, I'm a total n00b, can count the number of times I fired up GIMP!)
P.S. I know that fractions of pixels do not exist, so my rescale will round off, was just for example
And that I'm working in mm, just to get my scale look on the RC car body.
Hope this helps!
Thanks!
S

Between 1) and 2) there should be no change in print definition.

OK, so the problem isn't the copy/paste to the A4 image, that produces the right size in pixels, but why the A4 page doesn't print at the required size. One reason is that the A4 size as defined in the Gimp template covers the whole A4 sheet (210x297mm) but few printers can print the whole sheet, there are usually margins (in inkjet printers, a rather wide margin at the bottom for the feed roller) so the print driver may scale down the image to make it fit the printable area(*). Make your final image smaller (around 200x270mm)(**) to make it more likely to fit the printable area and see if it gets scaled down.

(*) you may be able to get an idea of your actual printable area using your word processor and doing a page layout for your printer. It may complain if you try to extend in the non-printable areas (note conditionals..).

(**) this assumes just a margin at the bottom, if the image is centered on the paper then you need to take in account a wide margin at top and bottom.

Sounds first that you are trying to create a sprite sheet with all your objects (sprites) laid out in a columns/rows situation, right? If all your sprites are of similar sizes, you can easily do this by first opening them all up as layers and then using your sprites plugin of choice. I suggest the python plugin below. As for sprite size, you have to have the dpi setting of each individual sprite to match that of your overall page size (say 300dpi for instance).

http://registry.gimp.org/node/1771

First, make sure ALL pictures have the same print resolution of 300 dpi. Once done, save each as, perhaps, «decal_1.xcf». Now reopen each picture and scale it to the correct size and save again. You should no have x files all in the correct resolution and the correct final size.

Then start a new A4 page from the template and make sure to have it transparent and check the print resolution. 300 dpi? Background colour transparent? OK, then save it too as, perhaps, «decal-base.xcf».

Now, reopen the A4 base and the first decal. Use the menu Selection? (the 3rd from left) and choose there «all». The picture should have now an ant line around it. Now you copy this all with ctr+c, and insert it into the A4 with ctrl+v. Make sure you then choose in the layers «make as a new layer» or somthing like this. Then you should use the »move» tool and push the pic somewhere else on the sheet. Do a save (ctrl+s) after each step.

Do the same with all your pics. You should now have a pile of layers, each with one pic in the correct size. Continue saving until the last pic is well placed.

Now, right click into the layer pane on the right and choose from the opening window something like flatten the picture, meaning to make one layer only with all pictures. ATTENTION and very important: you now EXPORT (and not save) this as, perhaps, «mydecals.png».

Now you close everything on your screen an reopen the new png file, print it our and you should have all individual decals in the correct size. png, because jpg is a lossy format and can not print transparency.

PS: sorry, I have no Gimp in English at hand, but ask, if you don't understand a command or where to find it.
I do similar things with up to 50 thumbnails for the production of small graphics for my wife.

Instead of Copy & Paste, try to do it different

I know printers may be fickle at times, but I went to page setup, set sheet to A4/landscape, source is auto select, and forced my margins to the minimum (L:0.066in R:0.49in T:0.133in B:0.133in). Also, when pasting all rescaled decals to the edge of the blank A4 template, always made sure to give 0.25in spacing from template edge, just to be safe. So, should I even touch the default edge margins? When creating a new template, the sheet I see onscreen is the entire workarea, or workarea w/margins included? Was I OK to space out edges?

Arran, will try to do do as suggested, from scratch, once again. Thank-you all for your suggestions, and will keep you posted on my progress. Wish me luck!
S

The print software doesn't care if the pixels on the edges of your image are used or not, they are taken in account when it computes the size of the image to print. You should really have an image that fits within the margins (3189x2362, if you use my figures above, instead of the .3508x2480 of the full-coverage A4).

I just verified all my sources, and unfortunately, I have both jpegs and pngs, and in the jpegs, many are 300dpi, but there are also a few 96dpi, and even one 72dpi. Cannot find 300dpi equivalents. Can I upscale them in any way? Can I save the rescaled sources in png? Wow. Gotta take this one small step at a time!
Cheers!
S

The only important thing in the size in pixels.

Just to add to what Arran and ofnuts said.

Standard A4 paper is 210 × 297mm. In Gimp a new Template: A4 (300ppi) 210 x 297mm (note the Advanced Options), is approx., 2480 x 3508px. To safely print this A4 template you need to set trim-guides 3mm from the outer canvas and safety guides 5mm within trim-guides for a total of 8mm. For example to safely print 8 logos using an A4 (300ppi) template each logo will need to be a maximum of 90 x 60mm, total canvas area (width 210/2 = 105mm, height 297/4 = 74.25mm).

Gimp doesn't have an A7 template so to test this 8 per page theory.
1. File | New, Template: A4 (300ppi), change w. 105mm & h. 74.25mm, leave the resolution at 300ppi.
2. Drag 4 guides 8mm from the outside edges (safety & trim-guides).

What you now have is a canvas in Gimp, print resolution 300ppi, sized for one logo (1/8 of an A4). Use this as a guide for sizing one logo of an 8 logo print. You will notice the pixel size is approx., 1240 x 877 px this is irrelevant for printing.

If you have a mixture of lower resolution logos, as a compromise, start with a reduced template resolution of 200-250ppi.

There are a number of ways to use this template.
1. Size logos, Copy & paste as layers into a new A4 (300ppi) template arranged for printing.
2. Layer logos in this template and use G'MIC | Arrays & tiles | Montage.
3. There is also CSS WebSprites script.

• Horizontal layers arrangement, side by side
• Vertical layers arrangement, one on top of the other

The key is to set your Print size and Resolution for each new canvas before you begin.

Arran, I followed your steps (with a few attempts/demystifying certain steps), got a fresh new approach on how to do it this way, and learned how to figure out transparency, making sure all pics are 300dpi & rescaled properly (few attempts!), then 'adding' that layer to the base layer. Finally exporting it as a png. Unfortunately, after printing out the final base layer:
1)realized that I went too far to the right, and all my decals got 'cut off' to some degree . I had set my layer in landscape mode, and had all margins set to minimum, thinking I was safe. Wrong. Is there a way to 'reshuffle' those cut decals, so as to avoid starting the sheet all over again?
2)Must have made some sort of rescale error in the first few decals, because they came out the same as my initial problem (!?). Can they be 'erased/replaced' by a corrected decal?


Ofnuts, learned what you meant by this, as I've realized that size in mm DOES change when your resolution is not unified to 300dpi, so after 'select all' and going to 'scale image' window, rescaled all to 300dpi.

So far, seeing some improvement over what I had before, a BIG Thank-You to everybody who shed some light on this for me.
The project continues....saty tuned!
Cheers!
S

Update....
I was really scratching my head on this one, with all your suggestions (thanks guys, you know who you are! ), and still having about 10-15 decals not rescaling right, until rescaled them some more. I had noticed that for some reason, they were all about 1.05 times smaller than desired, so seeing this pattern lit the old bulb in my head! Success!! I finally was able to print them out on my wife's newer printer, works better with my expensive paper, better resolution, etc. This is the RC monster which has been waiting for these decals...







...and the work I've been doing over the last few days..


Now, I've got to find a way to 'cut/paste' the logo on the tire in the photo, scale it to my RC tire, and I'll be good to go!


..to make it look similar to this


Once again, thanks guys for pointing me in the right direction, and helping out a n00b! I'll get the hang of this eventually!
Cheers!

S

Impressive stuff!
Good luck with the rest.

Be aware that A4 and letter are different sizes (8.25x11.7 versus 8.5x11).