Re: photo-like halftones
- Hi Rufo
This may have been discussed here and there but there is nothing on my blog. I am also going to transfer this over to PPL (if that even works), mainly because I am asked about it a bit, and hopefully it will have some sticking power there.
A solution/technique that seems to work was discovered accidentally by a student of mine many years ago. . . er, " by the assistance of the Most High, at whose bidding the tongues of children become eloquent, and who often reveals to the lowly what He conceals from the wise. . ." —Johann Gutenberg (assumed)
I've worked it out a bit over the years but note that this requires a great deal of trial and error to get to where you want it to go.
Yes, with any photographic reproduction you would need a very smooth paper though I have done this on mouldmades, like Pescia, at 150 lpi, successfully. Scanning resolution should always be at 1200 dpi in grayscale. You would bring the image into Photoshop and make two copies of it it.
The first would be the primary photograph which you would need to adjust for contrast and appropriate gray levels for output to letterpress. I believe this would be no gray levels less than 20%, or above 86%, building your contrast in the middle ranges. I'm guessing here as I am not looking at my notes on this but I think that is near the percentage range. This outputs at a dpi 1.5 to 2 times the projected lpi.
The second would be adjust primarily for enhancing contrast (a silhouette of the important details) and would be converted to B/W. 50% threshold at 1200 dpi.
The B/W or silhouette as it is rightly called is printed first. The halftone over it. Various transparent inks will provide appropriate color to either. Also blank panels of color printed first or last or both can help with coloration and enhancement. You should not end up with a dot pattern.
Note that you are making the photograph your own. This is not a technique to provide an exacting reproduction of a photograph image. But it is quite cool if you get it right.
If you have several honeycomb bases it would be best to do the experimentation with copper photoengravings. Or if you have several smaller bases for photopolymer. Obviously you have to get these all in register in preparation for the color work. Not a good idea for a solo base. Obviously this is not cheap nor quick and dirty.
You also have to clean the plate quite a bit for halftones to keep it from darkening at the edging (ink fill). In this regard copper would be best. Once you start cleaning a photopolymer plate you are walking into a quagmire. That is a whole 'nother post but there is something on that in my blog on the digital to analog page.
Hi Gerald,I have a project that requires me to reproduce a book cover in letterpress. The cover has a black and white photo in the center. how can I make this as photo-like as possible? You made some photo reproductions, and mentioned that you used two plate; a halftone and black. is this method outlined on your blog, or on the ppl listserve? What kind of paper and what plate preparation (scanning resolution, software involved) does this entail? I plan a small run; 20-25 copies. Any information on this would be most appreciated.Thank You,Rufo