magnesium plates vs. photopolymer?

I’ve noticed that a lot of people on this site use photopolymer plates. I only have experience with magnesium plates mounted on wood that I order through owosso & print on a vandercook sp-15.

Is it just a preference thing or are there advantages and disadvantages to one or the other? How about cost?

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I don’t think it’s just a preference thing unless you are just a mule-headed idiot. Photopolymer wins hands down. The problem, for both, is the base. You do not want wood in any case.

Now if you were to ask about copper plates vs. photopolymer, it would be a toss up, but still dependent upon the base. In this case photopolymer wins in cost but loses in longevity.



I have to take issue with what Gerald has replied to your query. Well-produced magnesium plates certainly can be as good or better than photopolymer plates. I don’t consider myself mule-headed, either.

I have experienced two problems with mag plates over the years, the greatest problem is with storage and re-use of the plates. They degrade when exposed to moisture in the air, and oxidize to a point to which they are no longer useable. The second is a matter of ink receptivity. The plates come from the manufacturer with a photo-sensitive coating which is not naturally receptive to inks. By simply cleaning off this surface prior to printing, the problem is resolved.

Perhaps there are other problems people have encountered, but for me those are the ones which have plagued me. I certainly can’t see the advantage of copper plates except for their use in hot-stamping as they conduct heat very readily.

Here’s the key. Much of the work I do is one-time use, so I don’t worry about the storage and re-use issue to any great extent.

I have switched to photopolymer to reduce my costs, not to improve the quality of the printing. If you have found a trade shop who consistently produces good magnesium engravings at a cost you can live with, I don’t see a good reason to change. Gerald is spot-on with his comments about mounting, but for smaller plate sizes, wood works quite well if it is dense enough.

Am I being a mule-headed idiot? I’m certain there other issues of which I’m not aware? Magnesium is more brittle than copper or zinc, but that has never played any significant role in any printing failures for me. I would like to see comments from others who use or have used magnesium plates and photopolymer. Are there really significant advantages to polymer plates?


thanks for your comment. I was begining to think that I was an idiot for using magnesium plates.

I haven’t had any problem with using magnesium mounted on a wood base. Except once with a very large plate the magnesium started to come off of the wood. But I reglued it and it printed perfectly. I haven’t done a lot of printing yet (still new at all this) but plan on picking things up significantly in the next few months. I started getting curious about photopolymer plates about seeing that a lot of people use these types of plates. I too mainly print only one-time use and never print really large runs.

As for storing the plates I use a food saver and store them that way. There’s this new thing called a Frisper that works similar to a food saver but the bags can be reused. I’m looking into getting one of those for the plates that I use more frequently to cut down on some waste.

Cost is going to come into play here shortly so it may be worth it to investigate further. From the research I’ve done the photpolymer and magnesium mounted to wood seem to be very comparable in price except for the cost of the base that you need for photopolymer . Do you make your plates yourself?

You’ve got me curious now.. i’m going to need to find someone who uses photopolymer around here and go see if I can tell a difference or if I prefer it.



You would think that “Gerald” makes his living selling photopolymer plates, or something?

This is total rumor and here-say, and should probably ignored but…

The word I’ve heard around the campfire is that metal plates such as magnesium and copper can stand up to high volume & heavy impression work better than photopolymer. This is particularly true if the form contains fine lines or delicate artwork, including fancy swirly fonts. I’ve also heard you can get cleaner fine lines and crisper edges on your text using the metal plates. On the other hand, I’ve heard that ink might spread more evenly on photopolymer plates than the metal plates, but… I’ve only ever used photopolymer plates at this point, so I wouldn’t be a very good judge of that. (And we’ve been very happy with our results thus far.) I’ve been curious about doing a “mag vs photopolymer shootout” though, to look for differences. I’m sure a lot depends on the ink, the form, the stock you’re running, the weather, which party is in the white house, and so on…

I will say that the photopolymer plates on the base thing pretty much rules as far as convenience is concerned. I often slip things around and make register changes right there on the base - without ever taking the chase out of the press.


I regularly use the photopolymer plates, and have been very happy with the results.
A couple of advantages are the ease of use and flexiblility of the material. You can see through it (if it is film backed not metal backed), which is nice for registration on the boxcar base.
It is also super easy to cut with basic scissors which comes in handy if i want to run two colors from the same plate, or if I ever need to run parts of a plate separately for varied inking coverage and what not.
It is significantly lighter in weight which can save on shipping and storage needs. I reuse plates all the time, many months later with no trouble.
The process by which the photopolymer is developed uses only water, versus some harder chemicals which are used in the making of the copper or magnesium plates, so that is a plus.
You can eventually make plates yourself , but i would not bother unless your production volume increases significantly. I would not recommend making your own magnesium or copper plates however, due to the chemistry.
There have sometimes been problems with tiny punctuation or lines wearing down when i use the film backed photopolymer, but metal backed photopolymer is typically very sturdy, and the film backed, if made properly, shold handle almost every job beautifully.
I think there are alot of advantages. it really is a nice material to use. The one time investment in the base is not too significant in the grand scheme and the time you save and the flexibility of the polymer are worth it, in my opinion.
good luck.

I am not expert…but I gave photopolymer a try and I found that the very small type was not printing crisp and I was losing some detail. So, I went right back to Mag. Not to mention that I spent some pretty good mony on a boxcar base…which is currently collecting dust.

Sell the base here on Briar press :)
I might imagine alot of material, like the wood that magnesuim or copper plates are mounted on, is also unfortunately wasted as it too collects dust after running a job.
The Boxcar base is reusable indefinately.
just a preference thing, and it seems more preactical to me, but i can completely sympathize if the you lost your punctuation, it is sometihing that dies happen on a rare occasion, and it can be frustrating
I will reiterate though, that in my experience, the photopolymer plates that are metal backed (and would therefore use a magnetic base, not a boxcar base) have never given me punctuation trouble.
But they also dont offer as much ease of use as the film backed photopolymer (easy cutting, see through registration), so perhaps you just land close to where you started.
Experiment and see what you like. :)

I talked to Owosso specifically about the oxidation on the magnesium plates and they said to lightly oil the plate after each use and to store them in an airtight container.

It’s been working for me so far but you need to make sure you do it after each use and to obviously clean off the oil prior to using the plate.

I’ve used Photopolymer, Myg and Copper and I think Photopolymer is no good. If you want a great crisp deep impression, I would go with Mag or Copper.

Anyone use a web base system for metal plates? I see everyone talking about boxcar bases, but those look to be a specific system for photopolymer plates. The Heidelberg KS at the shop I work at has a honeycomb system with clips to hold plates in place. There’s one job we get about every 6 months that they keep on a large one. I think our plate is steel as well as it doesn’t oxidize and doesn’t feel as light as some of the mag plates we’ve had made for foil stamping. I can try and get some photos if anyone wants.

I have used both photopolymer and mag for many years. Mag wins out easily over the former. For a substantial debossed impression, it is superior. Also, in terms of holding crisp, fine detail such as six-point type, mag prvides better fidelity to the original. If I’m printing a low-budget, fly-by-night job for someone who can’t tell the difference, photopolymer will save a few bucks. For impeccable, award-winning work, magnesium would be the only choice.

Craig Malmrose

What would be the ideal base coupled with copper plates? I’m talking very best possible print for line art, pen & ink conversion. Thanks

Bases for photoengravings were pretty much all for 11-point duplicate plates, about .1522” (patent bases such as honeycomb, diagonal groove, sectional, etc., with honeycomb the only system still made). Original photengravings were usually about .060” and were usually mounted on wood, occasionally on lead; to mount on patent bases you’d have to add a backing sheet both for height and to get enough body for the hooks to hold. You can get copper photengravings at .1522” but they will be more expensive than .060”.
Mounting original plates on lead is still done iwith .854” lead high base cast in strips on the Elrod. With a printer’s saw it is easy to cut pieces and assemble a base of appropiate size. Plate is mounted with double-sided tape (works with photopolymer too). But wood works too; if you have the capability to plane or shape mdf board to the suitable thickness. That could potentially be more accurate than the plywood base your photengraver can buy today.
Lammy, copper was sometimes steel-faced for longer wear, but that will oxidize if not coated for storage. Nickel-facing was a former practice too. But a solid steel plate seems unlikely. What does a magnet tell you?