This topic reappears often enough that it suggests a need for a comprehensive overview of the subject in, perhaps, an MR article or an MR website online feature.
I have been making my own decals for several years, as I enjoy repurposing older rolling stock I pick up at swap meets.
The variety of decal paper manufacturers and methods of making decals (as well as clear vs white decal production methods and issues), how to properly prepare the receiving surface, after-application decal treatment and a discussion of different production devices (ink jet versus laser printers, 3-ink color machines vs those with additional differentiated color cartridges) may provide many modelers with information that would help the achieve more consistent results, improve decal quality, and also encourage others to become involved the decal making process.
One note: other than mentioning Alps printers (for white lettering) in passing, as these are no longer a viable option, being out of production, any discussion of alternate white letter decal making should focus on white decal paper- the only current method feasible.
I know I have replied to at least 4 long threads on decal making over the past 2 years and it seems there exists a significant number of modelers who have questions about this topic.
Cedarwoodron
I'm pretty sure that articles on making your own decals have indeed appeared in print - for example year ago didn't either Lance Mindhelm or Pele Seoborg show how to make custom decals to model road details like manhole covers and drains (or perhaps that was in the dimension, cant really recall).
cedarwoodronI know I have replied to at least 4 long threads on decal making over the past 2 years and it seems there exists a significant number of modelers who have questions about this topic.
chutton1
You are correct that getting the right background color mask is a little "fussy" as the screen color rarely matches the printed color and the printed color varies with the paper used. I have found that the best way to achieve the best color match is to create small test swatches along one edge of the decal paper. Don't test on regular printer paper because it takes the ink differently than the actual decal paper. I start by creating small squares along one edge of my computer design page. I then try to choose a color that appears closest to the model paint and assign that color to the middle square. I then assign gradually darker shades of that color to each consecutive square to the left of the center square and gradually lighter shades to the squares to the right of center. I print these squares on the decal paper, let the ink dry at least 30 minutes, then compare the printed colors to the model. I usually find that one of the squares is a good match but sometimes find the paint color is between two of the printed squares. However, this also allows you to adjust the decal color to a closer match.
Once I find a good color match, I name it (such as Accurail ATSF Oxide) and save it on the computer for future use.
As far as Ronsonol changing their formula, I just bought the bottle I have about 3 weeks ago and it worked quite well setting the Evan Designs decals.
Hornblower