Getting decals to print the correct size

[Foxer]

This tutorial is about making decals from bitmap photos. I do this often when building cars I've owned and many times I don't even have the car to reference for photographs.

1. Decide what you will need photos of and either take pictures with your camera or get on the internet and Google those you'll need. I'm going to use a 1969 Volkswagen Beetle I'm building as an example. I needed decals for window stickers, license plate, dash gauges, bumper sticker and rear lid VOLKSWAGEN nameplate. I sold this car over 40 years ago so I couldn't run to the garage with my camera. I think the bumper sticker I may be able to grab from a couple scanned slides I have. The rest came from internet images I found.

2. I use Photoshop to edit images but there are many other affordable graphic programs out there that do just as well. It is VERY helpful if the program has layers as this makes things much easier. I'm not making this a Photoshop tutorial but will give the steps I used to get things to size ... this should be easy to translate to your own program.

3. Once you have edited the image to erase backgrounds and isolate the part of the image to be used it's ready to be resized. I typically make two final files of all the decals ... one for clear decal paper and one for white decal paper. If any of your decals need white you have to use white decal paper. Hopefully these can be rectangular over all as you will have to trim the image right to the edges. I have one image, the VOLKSWAGEN nameplate for the rear engine cover that has to be on white paper and is impractical to trim. I'm going to try a trick promoted by Harry Pristovnik which entails making the background color the same as the body so only the name plate will show. I'll report later in this thread how successful I am at this!

4. To size the images to scale I first crop the image as close to the edges as possible. I then find the actual size of the decal I need in inches. This may be an actual measurement off the model with calipers or from the real world size. If you have the real world size, divide that by your scale. For instance, a US license plate is 12" wide and my model is 1/24 ... divide 12 by 24 which equals .5". So, the decal of my license must be .5" wide. When resizing images I don't "resample" the image .. I don't change the number of pixels ... just change the images size in inches ... the resolution (pixels per inch) will go up. These are Photoshop terms but yours may be the same. Just pay attention to the concept.

I get all the individual decals to this point.

5. Now you have to decide at what resolution you wish to print at. Usually 300 DPI (dots per inch) is adequate for most inkjet printers. I have a very high level inkjet that will print at over1500 dpi so I usually make the decals at 1000 dpi. This also helps low resolution images that break down at 300dpi. This is personal but I find it works fine. I create a new image that is 8.5" x 11" at 1000dpi ( or the resolution you want to use) to copy all the separate images to for printing.

6. Transferring all the images you have prepared in step 4 requires making the resolution match your print resolution image ... 1000dpi in this case. I do this in Photoshop by changing the Image Size with Resample turned on. I just change the resolution to 1000 so the image dimension remains unchanged. You will have to check how your program sizes images to leave the dimensional size alone and just change the pixels per inch to your print resolution. Now when you Copy (ctrl C) the individual image and paste (ctrl V) to your "all decals" image it will appear with the size correct in relation to all the other decals and the correct size for printing. I just arrange the decals along the top of my 8.5" sheet and print. Most of the time this is only an inch or so so I trim them off and use the decal sheet for the next ones I'll make.

Hopefully you can make sense of this text only tutorial so pay attention to the concept behind it all and you should have no problem sizing your decals and even using something different than Photoshop.

Here's a shot of the '69 Bug white decal sheet as an example .. with license plate, fuel gauge and speedometer. I always make a few extra just in case.

Edited May 24, 2013 by Foxer

[sjordan2]

One thing that makes reduction in size a little sharper on my inkjet is to keep the base art as large as possible, allowing me to print out at sizes down to 25% of the original. Not a big move, but it seems crisper to me.

[Ace-Garageguy]

Good job explaining the concepts clearly and concisely. I'm saving this one. Thanks.

[ScaleDale]

Here's my take on step 4, scaling the image to the correct size to fit the model.

I scan either the technical drawing from the first page of the instructions or the decal page from the same into a file that is the same resolution as the decals I will print. 300 dpi RGB color for my purposes. If I want to verify the scale I look up the factory wheelbase of the vehicle and scale the image to match it after dividing it by 25. After making sure all my decal images are 300 dpi RGB, I import or Place them into this scaled document and size them as I please.

When I'm done I either copy them back to a new document to prepare for print or just delete the vehicle layer.

Other decal notes:

Don't use clear paper to go over dark paint. You will be disappointed with the results unless you have a very good printer.

Dale

[Tom Geiger]

For gauges and license plates, you don't need to print those on decal paper. I print license plates on 60 lb bond paper to give them some thickness. I then use a white glue to affix them to my model. I print gauges on everyday 20 lb bond paper. Again I cut them out and glue them in place with white glue. I use the stuff made for model clear windows. A blob of it over each gauge makes them look like they are under glass once it totally dries.

For those of us without Photo Shop, I do most of my decal sizing in Microsoft Word. I will import the image and scale it within Word. Sometimes when I'm working with images that are coming from a source that isn't scaled, or I have to approximate a fit onto the model, I'll scale it to a bunch of close sizes, (like scaling the image to 30%, 28%, 26%, 24%), then printing the page on paper. I can then cut out the images and place them over my model until I find the size that I want. Once I know that, I will copy a bunch of that same image on my page and print another test shot on paper. Now to save decal paper, I will see how big the printed image area now is and cut a piece of the decal paper to cover that. I tape the leading edge down and put the sheet back in my printer. Now when I print again, I'm printing on the decal paper!

Note that word as a whole slew of lettering fonts and color choices. So if you need to print some lettering along with your photo decals, you can do that at the same time.

[Foxer]

I'm happy everyone is adding their experiences here.

As Tom says, I use a lot of copy paper for testing size even when I'm sure I have it right. That's a great idea Tom explains for programs like Word with no scaling, per say.

[DanielG]

I use PrintArtist. I use photopaper for things like gauges and plates.