Re: [PPLetterpress] Re: Exposure/washout units
- Dear Gerald
The exposure for the KM 152, depending on image, the more solid the
shorter, is for about 2.5 minutes and wash out about 3 minutes. I have
found that this material is easier to wash away. After about two and half
minutes I will check with a loupe every 15 to 30 seconds until the bevel on
the edge is correct and that the periods, dots over 'i' and end of lines
are not undercut. The arrangement of positive and negative space on the
negative will affect this.
I will use the KM 152 for solids, when the general image is large
(backgrounds, large block type etc.) While this material is capable of
holding fine lines I find when printing that it is a softer, more generous
and will spread more than the MLD. The 152 is great for printing on plastic
and responds best to soft packing.
MLD after the final exposure is quite hard, but brittle, and holds up to
the letterpress look (deep impression) that is so popular today. I have
found it holds fine lines and dots with a longer washout than the 152. The
longer washout is important, it reveals the edges of the typeface, washes
away the shoulder and makes the printing more accurate as to its design.
Especially on the different surfaces and thickness of paper. Printing is
primarily on 10x15 Heildelbergs' and 21x28 Heidelberg cylinder presses.
I don't remember how I got to this choice but it has worked so well I
haven't found a reason to look further. Most problems are operator error
either in how I made the plates, my make ready or some mystery that is
plainly obvious to everyone but me.
I think the spec sheet I have for MLD recommends it for all the
processes you mention but I thought it also included letterpress. I will be
at the shop tomorrow if it is any different I will send you a note.
What material do you use?
Gerald Lange wrote:
> Dear Frank[Non-text portions of this message have been removed]
> Since we are using the same machine I have some questions I hope you
> will address. I also keep the temperature down a bit. 90 to 100 max
> for KM 95s (.038).
> But I would like to know your exposure times for KM 152 (.060). You
> wash these out for four minutes right? What are your exposure settings
> here for say reverses,/solids, then type, then fine lines/halftones?
> And a curious question, why MLD 145s for text? These aren't even on my
> spec sheet for letterpress!!!! Aren't the MLDs for molds, hot
> stamping, flexography, rubber stamps, etc.? How did you get to this
- Hello Gerald & others,
With such variations apparent in different plates, it would help my
perspective if you might label the brand or source of the various plate
materials you are describing. I am using Gene Becker's Miraclon MS152 plates
in a home-made, handwashed system, getting good results (within a long
process of adjustments and fine tuning and experimenting). But I am
continually amazed at how divergent everyone's answers are: I hardly ever
hear the same instructions, exposure times, washout times, proceedures, etc,
despite how certain and enthusiastic we all are about our results. I have
projected the same certainty at times, only to realize later that I had
misinterpreted some factor or another. Correctly diagnosing problems in this
technology remains a humbling mystery, despite my being able to use it
successfully for numerous commercial and artistic projects.
Another request: I wonder if someone might describe the machine washout. Does
the machine fill up with water and soak before brushing? Or maybe pause
brushing and soak occasionally? For how long? Or is it all continuous action?
And is there any method used for observing/evaluating the progress, or is it
just a timed setting? In hand-washout, I am continually checking, and choose
to halt early or continue washing down to clean metal backing according to
the specific details of the plate. I have wondered how this could be possible
in the machine.
Any rate, thanks for carrying on so -- I'm listening with interest.
Best wishes, Tom
Now It's Up To You Publications
157 S. Logan, Denver CO 80209
- Dear Tom
Don't really know how to address the first issue. Economics is a big
factor here. If you are not doing "industry standard" (and to do so
requires owning variously expensive equipment; processing machine,
bases, etc., all of which have their own uniquely varied
requirements) you are doing "alt," and in alternative processing the
techniques and materials employed are so varied, subjective, and
discontinuous one to another that to speculate on their relative
merits or demerits is foolhardy.
I'd like to think this must be somewhat akin to the problems that
Monotype must have faced. Now that they've potentially put a possible
foundry into every printshop, how do they regulate it? Their answer
seems to have been, to not regulate. Give the caster the ability to
alter character positioning, metallurgy, type height, etc. Hmm, maybe
not the best analogy after all.
Maybe I can do better on machine washout. Well, the machine should
fill up with water to some point just above the brushes. My rep says a
quarter of an inch, and I believe every word he says. The machine has
a cyclical pattern that seems to brush, halter, and brush again. It
could be reversing the pattern, I do not know. The machine is closed
during the process. The halting is only for a second or two. The
machines are timed-set. It is initially a matter of trial and error to
find the correct timing though there is certainly enough info out
there to get you on the right track quite quickly. This of course
various with different configurations of plates. Nothing but variables
in photopolymer I'm afraid. Trick, I quess, is to find your own here.
Regarding the checking. I never do this. I don't know what I could
tell by what I was seeing anyway. This may probably be a good idea,
whether you are doing this by machine (as Frank does) or by hand (as
you are), but I assume you need the eye for it. If I've had problems
(other than the purely mechanical) they have generally been in exposure
because I have knowingly taken shortcuts, specifically, ganging plates
or running different weights of text or formats together or, the worst,
saying yes to the client who prefers to furnish their own plates. I do
a certain amount of hand washing out for a specific kind of plate and
I try to mimic what I believe are the actions of the machine. I have a
little contraption built for this that I use in the machine, against the
brushes; I think I may have mentioned this in a very early post. Personally,
hand-washing scares the crap out of me. I do a lot of bookwork mainly so
consistency is quite crucial to me. I'm under the opinion that seconds
count here and I don't trust variables in regard to processing.
Doubt if this answers or resolves anything. But it was a good question
and, since no one else jumped at it, I thought it worth a shot.
> Hello Gerald & others,
> With such variations apparent in different plates, it would help my
> perspective if you might label the brand or source of the various plate
> materials you are describing. I am using Gene Becker's Miraclon MS152 pla=tes
> in a home-made, handwashed system, getting good results (within a long
> process of adjustments and fine tuning and experimenting). But I am
> continually amazed at how divergent everyone's answers are: I hardly ever=
> hear the same instructions, exposure times, washout times, proceedures, e=tc,
> despite how certain and enthusiastic we all are about our results. I have=
> projected the same certainty at times, only to realize later that I had
> misinterpreted some factor or another. Correctly diagnosing problems in t=his
> technology remains a humbling mystery, despite my being able to use it
> successfully for numerous commercial and artistic projects.
> Another request: I wonder if someone might describe the machine washout. =Does
> the machine fill up with water and soak before brushing? Or maybe pause
> brushing and soak occasionally? For how long? Or is it all continuous act=ion?
> And is there any method used for observing/evaluating the progress, or is= it
> just a timed setting? In hand-washout, I am continually checking, and cho=ose
> to halt early or continue washing down to clean metal backing according t=o
> the specific details of the plate. I have wondered how this could be poss=ible
> in the machine.
> Any rate, thanks for carrying on so -- I'm listening with interest.
> Best wishes, Tom
> Tom Parson
> Now It's Up To You Publications
> 157 S. Logan, Denver CO 80209
> (303) 777-8951
I had thought, much like you do, that hand-washing would be accurate
than machine washing--until I recently switched over to a machine
washout. I purchased the machine for better exposure and for
convenience, but didn't anticipate better washout.
In fact, the machine washout produces noticeably better plates. The
main advantage to the machine is its evenness of pressure. You don't
need to check the plate periodically for unwashed areas because the
whole plate washes out at the same rate. Corners took notoriously
long to wash out by hand; now, I don't have to worry about overdoing
the washout in the center. This isn't such a problem on type, but a
10% or 5% screen in the middle of your plate will suffer from
excessive washout. Because its pressure is constant, it doesn't tend
to wash away isolated dots as easily.
Since the machine brushes are larger, they also get the plate out of
the water sooner. Some plates, especially the large (say, 11x17)
ones, had to remain underwater for 10+ minutes to wash out with a 4x8
brush. Leaving them underwater so long can cause delamination of the
plate. Oh, and the machine brushes don't have hard plastic corners
that can scratch the surface of your plate.
Handwashing works. Telling the difference between a machine washed
plate and a hand washed plate (by someone who has excellent
technique) would be impossible on most small plates. But for large
plates or ones with isolated dots, light screens, or very small text,
machine washing works much better.
- Thanks Gerald,
Your description of the washout machine action is about as I imagined, having
only seen one not in operation. My washout time is presently quite a bit
longer than others have mentioned, perhaps because I use a very soft brush
and only very gently agitate. Obviously still some room for experimentation
here, but my results now are quite consistent and it seems possible to
control it by hand washing.
My first question was probably simpler than your answer: just that the plate
references (such as MK or MLD) don't tell me much unless I am using the same
source for plates, I think. Would the MK152 be the same as the MS152 I get
from Gene Becker? Maybe I just need to go back to the various notes Gene gave
me to see if the answer is there. Similarly, I have had some difficulty
making comparison with materials supplied by NA Graphics, because the names
differ. So I thought it might help if I say Gene Becker's Miraclon MS152
rather than 152 or MS152....
Regarding toxicity, it sounds like it's a question of skin sensitivity rather
than poison or carcinogin. I have hand-washed maybe 40 sheets (A3 size,
297x420 mm = 11x15? cut to innumerable smaller plates) over six years or so.
No gloves. No noticable skin reaction, no other problems at all (except an
occasional cut from the sharp edge of the metal backing, of course). I do
keep the water running slightly (to keep the temperature constant) so maybe
the concentration is low. Or maybe I'm just not sensitive. So far, it seems
to me remarkably benign. The very slight odor from unexposed material also
seems inconsequential to me. UV light, of course, is bad for the eyes (and
skin as well, I think).
Best regards, Tom
Now It's Up To You Publications
157 S. Logan, Denver CO 80209
- Hello Tom,
The orbital washout unit has been the only way I have been able to produce
consistently good plates efficiently. The time factor is very important.
About twenty years ago, when the photo polymer was just entering the
market, I was told by salesmen that the plate could be exposed in the sun
and washed out in a sink with any brush. I spent what seemed and endless
amount of time discovering only that there are many variables. I built
things, converted things, nothing I did seemed to have the same results
twice, or that the plates were just not good enough. I like process, but I
was always off task trying to find a solution.
While not quite a glorious epiphany, the machine allowed me to make
accurate plates, in a short time with not so much guess work. I only had to
pay attention to the orientation and density of the negative, the suction
of the vacuum table, cleanliness of the kreene, monitor the wash out, water
temperature, drying and final exposure to harden the material. The process
is simple and consistent (generally).
I like to examine the plate during washout to check that as much
material has washed away as possible but not so much as to weaken its
structural integrity , (small bits of the design, or letters that break off
during printing that you don't notice until you are finished).
Gerald has a good explanation of the washout process.
I think Monotype had much more exacting details built into their
production, and while success at times seems atmospheric the documentation
they provided would allow you some success. There are just so many pieces
to pull together and each one requires complete attention to detail.
If you contact me off list I can send you some plate processing
instructions for Miraclon/Rigilon, this is the MLD made by Toyoba. They
also recommend it for crash printing, hot stamping and for pantograph
masters. I have only used it for letterpress printing.