Home printed decals 'leaking'

[PR19_Kit]

Both Fred Zenrat and I have had this issue recently, where the colour of a home printed decal leaks out of the decal itself and spreads across the model where it's not meant to be.

After a lot of checking back, it occurred to me that I'd only had it when I was using white decal paper so as to match some background paint that was already on the model. Using white paper you have to trim VERY closely to the decal image or you can see a border of white decal round the edge, and that just won't do. I came up with this theory, and the drawing below shows what I mean.



These sketches show a greatly magnified view of a cross section of a three different types of decal.

The first sketch shows a commercial decal where the varnish is spread nicely over the image and seals it at the edge. 99.9% of the time they're printed on clear decal paper because they can print white.

The second sketch shows a home printed decal on clear paper which been trimmed as close as need be because the varnish is invisible so it doesn't have to be trimmed right up to the edge of the image. No water can get at the ink as the varnish prevents it.

The third image shows a home printed decal on white paper which been trimmed right up to the edge of the image as otherwise the white will show at the edge. In this case the water CAN get directly to the ink as there's no varnish to prevent it doing so, and this results in the ink leaking out all over the place.

That's my theory anyway, anyone want to add things to it?

I've no idea how to solve the problem I must admit, but the idea is out there.

[jcf]

It's definitely an issue with inkjet printed decals, but is it an issue with laserjet printed decals?
🤔

I suppose one thing that could be a possible solution is to cut the decals out before spraying
them with the sealing varnish. How to hold them down/in place for applying the varnish would
be the fiddly bit.

[The Rat]

How to hold them down/in place for applying the varnish would
be the fiddly bit.

Tiny little piece of double-sided tape.

[frank2056]

It's definitely an issue with inkjet printed decals, but is it an issue with laserjet printed decals?
🤔

Laser printed color decals can have the toner flake off. ALPS decals can crack and have small bits flake off as well, especially if it's a multi-layer print. Both are sensitive to scratches so the best solution is to seal them as soon as they've dried onto the model. Neither has much of an issue with water seeping in through the cut edges, since neither toner or dye are water sensitive.

@Kit - great graphics!

[Beermonster58]

It's definitely an issue with inkjet printed decals, but is it an issue with laserjet printed decals?
🤔

I suppose one thing that could be a possible solution is to cut the decals out before spraying
them with the sealing varnish. How to hold them down/in place for applying the varnish would
be the fiddly bit.

How to hold them down/in place for applying the varnish would
be the fiddly bit.

Tiny little piece of double-sided tape.

How about using stamp hinges? I very rarely use white decal paper anyway but, on the occasions I did, I hadn't encountered this issue. I wonder if it's the particular paper used or, ,maybe a general issue with white decal paper? I only use an Inkjet printer so, I cannot comment on Laser prints. I also give at least three coats of sealer but, I don't know if  that would make any difference.

[PR19_Kit]

I've no idea if it's an issue with laser printed decals as I've never used a laser printer, I can't afford one.........nor an ALPS printer either. I don't think I've ever SEEN an ALPS printer actually.

I'll give the idea about cutting them out before sealing a go, at least on a largish decal anyway. I'll need to do the find decal on my Super Sealand on white paper, and it's quite large, so would make a good test case.

[zenrat]

I agree with Kit's theory.  I've thought the same.
I have wondered though.  If one cuts out the transfers before spraying the clear then clear will be absorbed into the paper at the edges.  Would this affect the release of the gelatin layer from the backing paper?  I suppose trial and error is the only way to find out.

When I clear my transfers I use small blobs of blutac to stick the sheet to a piece of board.

My transfer problems were not helped by using hot water to soak them.  I think this caused the clear to shatter which allowed the water to get to the ink.  I was also moving them around a lot on the model which exacerbated the damage. 
Once I put on heavier clear coats, used lukewarm (almost cold) water, and tried harder to slide them into the correct position first time then I only had minor damage in a few places around the edges which I could touch up with paint and a very thin brush.