Pin registration system preferences

[Pere Casals]

this thread was concerning color separation negatives and how to precisely register them - and those aren't meant to be diffused !!!!!!!!

OP says negative printing and color separations, and the first thing may use diffusion.

Digital masking can be very useful for RA-4 optic printing. I allows "through the negative quality" while it adds some of the "hybrid flexibility". Imagine a wedding shot, a white dress would impose a color balance, but beyond that you may want (say) a cooler background and warmer skin tone, you may do that by editing a color correction mask in Ps that corrects color locally and dodges certain areas. You save time and materials. In that case you need some diffusion to hide the inkjet spots in the mask. Then you have solved most of the print, it may be left some manual burning.

[Drew Wiley]

That seems to be the wrong post, Pere, so I can't comment. What you're missing in this whole conversation, because you're still hypothesizing about all this, is that in color printing, masks are used not only for contrast control or curve modification, but for color correction too, in advance of separation negatives, or in combination with them, or just by themselves when separations are not in mind. It makes little sense to do half of this via scan and the other half via film contact directly. Besides, unless you're generating especially big digital separations, it's far easier to register thing everything using actual film the whole way. The method you espouse would be clumsy at best attempting hue correction in fine detail and not just overall areas. But you are obviously welcome to experiment. I've only been actually doing this kind of thing for the past forty years, so what would I know?

[interneg]

Greg - good to get a double confirmation on the Condit pins - if you could send me a picture of the punch, I'd be interested to see how it changes between 4x5 & 8x10 settings.

Drew - you're hitting the nail on the head with what's wrong with Pere's approach. It's imprecise in register, overly time consuming/ effortful for the end result vis-a-vis what a competent printer can do in a few minutes (which is not to deny that Alan Ross's approach using yellow & magenta selective masking has some usefulness in long edition printing with complex negatives) & starts from the (wrong) position of making a notionally 'correct' print rather than one that looks 'right' - which is, I think, the fundamental fault of the BTZS approach as practiced by many - it's fine if you need an exact replica of something like a car part or a painting etc, not so good for creative approaches. Essentially its adherents seem to spend an awful lot of time imposing a top-down set of technicalities on image-making rather than using it as a means to analyse/ standardise a film/ paper/ exposure/ process that makes a 'good', as opposed to 'correct' print - often, I suspect, because of an unwillingness to open up to the hard work and artistic understanding necessary to get better at printing. Attempting (and failing) to turn complex human understanding and behaviour into reductive tables of numbers has been an irresistible technician's temptation for many centuries.

[Drew Wiley]

Well, creativity also depends on one having a bit of fun doing things the way one wants to, whether entirely realistic or not, otherwise a procedure becomes tedium. So I can't dictate rules to anyone else. But some methods are indeed much more efficient than others in terms of getting from Point A to Point B without a train wreck. Now as to pin diameters, the problem with anything a bit over 1/16th is that some films swell with humidity, and once that tiny hole becomes too tight, it will break open when forced onto a pin. But shrinkage of film can be even worse. Alas, for awhile polyester base color film choices were scant, and we had to make due with dimensionally unstable acetate base. A barely undersized pin like 1.5mm seems more practical to me. Mine were very precisely made in Italy, but purchased through McMaster. I have no idea who made Condit's offset pins, but the source and quality obviously differed over time. All those pins ended up in the hands of Jens of DurstPro when he purchased Condit, and have hence disappeared into the blue like him. Larger offset pins are available from American Circuit Technology, but then you'd have to match everything to their own standard. They do offer custom mfg, but people like me who pretty much has everything necessary anyway, and might buy only two or three pins some day, are hardly realistic candidates. I guess it wouldn't hurt to ask them what a minimum quantity order would be for 1/8" barrel / 1/16" off-center upper pin configuration. Maybe they've done that size before, maybe not.

[Drew Wiley]

Pere - with respect to merely masking color neg film : in the case of a basic contrast-reduction mask, you can go diffuse. But if you need a contrast-increase mask (a distinct possibility when working with low contrast color neg film), you first want a sharp contact interpositive, prior to your unsharp mask. I guess you could hypothetically reverse an image after a scan, going directly negative to negative in PS, but you'd have to figure that out on your own. But that still leaves you with the difficulty of color-resolving fine detail without registration headaches. A pin-registered film recorder could solve this automatically, but that's a pricey option. Have fun.

[Pere Casals]

But if you need a contrast-increase mask (a distinct possibility when working with low contrast color neg film), you first want a sharp contact interpositive.

OK, I understand what you say, with diffusion a CRM increases acutance, instead with a Contrast Increase Mask what diffusion does is adding some blur.

We usually never require a Contrast Increase Mask in BW in optic printing because we instead rise the paper grade... but OK, we may want a contrast increase mask in RA-4

In theory we can digitaly edit a mask that both increases contrast and acutance when diffused, in the digital edition we have powerful tools like the highpass filter that can be subtracted from the original image and later layered on our mask, this is in theory, I'll dig in that...

Personally, I've advanced a lot in digital masking with BW, I found it extremly powerful. My next step will be trying that for RA-4, I suspect that it would also deliver a nice flexibility.

"Throught the negative quality" combined with some of the hybrid flexibility may be a powerful combination !

This woud also require registering, tinny marks are placed in the negative boundaries, this allows an easy alignment of the mask with the negative, and correcting the mask size to perfectly match (we only need to inkjet print the marks). When alignment made the digital mask is registered with the negative, for convenience, to not have to align anymore the mask again with the bino loupe.

[interneg]

Pere - I know you like to throw around the acronyms used by the Radeka et al school of masking, but before you deny the usefulness of sharp highlight 'bump' masks in BW, please go and at least read up what they and Ctein have to say about their uses.
Furthermore, inkjet masks are useless for any sharp masking above contact size because of the stochastic screening - indeed, the granularity of any sharp mask film is an important consideration that must be made. And that's before we consider the inherent effects on contrast that a halftone screen has.

[Pere Casals]

Pere - I know you like to throw around the acronyms used by the Radeka et al school of masking, but before you deny the usefulness of sharp highlight 'bump' masks in BW, please go and at least read up what they and Ctein have to say about their uses.

Interneg, if you read well I've not denied that, as I was not speaking about masks intended to selectively modify ("Bump") highlights, I was saying that Contrast Increase Masks (counter of a Contrast Reduction Mask, CRM) are not usually made for BW printing, because by increasing paper grade we do mostly the same without making a mask.


Instead CRM may often be needed to deal with extreme DR in the scene.

Furthermore, inkjet masks are useless for any sharp masking above contact size because of the stochastic screening - indeed, the granularity of any sharp mask film is an important consideration that must be made. And that's before we consider the inherent effects on contrast that a halftone screen has.

Interneg. Unsharp masking. In unsharp masking the faint interpositive mask always has to be diffused anyway, to get higher acutance. Using a diffuser layer is the usual situation in masking, and this allows using an inkjet mask.

[Drew Wiley]

Pere, I think you'll eventually discover two serious problems with inkjet masks when it comes to COLOR printing, besides the necessity to manually post-register them. This method is nowhere near as sharp or accurate as film by contact, even slightly diffuse. Second, black inks suitable for printing on transparent substrates aren't truly black, but carry some kind of hue bias. This is a significant problem where you only want some shading effect, as in fact is the case with most contrast masking. You will probably have to take a hard look at ink selection and experiment. So things get a little more complicated than using your prescribed method for black and white printing. But, as usual, you're welcome to carry this to its logical endpoint, and see whether or not it's sufficient for your own needs. It seems more like an unnecessary detour to me, with a bridge or two out along the way. But if you enjoy this approach, see where it takes you.

[Pere Casals]

This method is nowhere near as sharp or accurate as film by contact, even slightly diffuse.

Inkjets deliver 6 lp/mm aprox, which is sharper than the diffusion in a USM, so no problem.

Second, black inks suitable for printing on transparent substrates aren't truly black, but carry some kind of hue bias.

This is not a problem, we may correct hue of the black ink with the CMY inks we also have.

But if you enjoy this approach, see where it takes you.

We'll see

Approaching optic RA-4 these days is uncommon and it may look weird...