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sperdynamite
27-Sep-2016, 10:13
Hi,
I have a better scanning wet mount holder and I'm finally getting around to doing the height calibration. I was thinking that some newsprint might actually be a good test target for focus. Does anyone have any other ideas or is there some reason why I should stick to actual film.

Thanks!

DrTang
27-Sep-2016, 10:17
you gonna shoot a neg of the newsprint? that could work

sperdynamite
27-Sep-2016, 10:20
No I was thinking of literally just newsprint. I think the scan will show the fibers pretty well and the pattern might be good for judging detail. Maybe thats just crazy though! haha

DrTang
27-Sep-2016, 11:00
the holders are for negs/transparencies - and not flatart -

I would just shoot a high contrast shot of newprint of the film I use and use that

Doug Fisher
28-Sep-2016, 08:12
You definitely do_not want to use newsprint.

You need to use film. A piece of film with a scene that has lots of detail on it (e.g. a street scene with lots of buildings or signs in the distance) is usually all that is needed. Even better, find the dark unexposed end of a developed film strip and use a paper clip to scratch a cross hatch/grid into the emulsion all the way across the entire piece of film. Adjust your scanner settings so the scan doesn't blow out the hatch pattern and you will see that the edges of the scratched emulsion have fine detail which is excellent for judging sharpness.

Doug

Jac@stafford.net
28-Sep-2016, 08:35
Try something simple first.

In ordinary room light score an unprocessed negative on the emulsion side with a fine pin or dental probe (found at hardware store). Fine scratches vertical, horizontal and diagonal. Develop in daylight with Dektol, then fix. Now you have a target with varying lines.

EDIT: Sorry, Doug. I did not read your similar suggestion.

Jim Jones
28-Sep-2016, 14:56
Rather than scribe scratches, use coarse and fine sandpaper to lightly sand one surface of a sheet of film in a random pattern. I haven't tried it with a diffuse light source, but it works great in condenser enlargers.

Pere Casals
5-Oct-2016, 16:03
Hi,
I have a better scanning wet mount holder and I'm finally getting around to doing the height calibration. I was thinking that some newsprint might actually be a good test target for focus. Does anyone have any other ideas or is there some reason why I should stick to actual film.

Thanks!

I've done this recently.

You may use a USAF 1951 glass slide pattern, search the popular auction site, you'll find a chinese source for $85 or best offer, so offer some $60. That slide is 63x63mm, you have to place it emulsion down, as glass is thick this is not like film. It may not fit in the 120 holder, so take a high resolution (CMS20, TMX) film and make a contact copy.

Then you have to locate the Group number and Element number in what you see if bars are Hor or Wert, going to the USAF 1951 entry table you'll know how many line pairs per mm (lp/mm) are seen, so adjust to optimal heigth.

Those chinese slides may have some defects in the smaller elements, but for the price they do the job.


This is a little investment but you'll know scanner performance. If you convert lp/mm to dpi you'll see some 2300 to 2600 dpi, depending if it is Hor or Vert axis.

Also this can be useful to rate performance of your lenses, and to find best aperture for center and corners... Also you can use that slide to obtain a paper contact copy, or you can use the same slide with a backlight. If slice is say 6mm on the GG magnification is 1/10, then if group/element says 4lp/mm resolution will be x10, 40 lp/mm.

It can be also useful to rate film resolution, by inspecting a film contact copy with a 60x magnifier. Also you can rate paper resolution, looking 60x the paper contact copy. And finally you can rate your enlarger lens, by projecting the slide on paper.


A final advice, about result quality, if you have not a Silverfast version that has multiexposure you can buy one in that auction site. This enhances a lot results in some cases. The silverfast version that comes with V700 do not makes multiexposure, whole the V700 can do it. I think that add-on feature can also be purchased separately.


Regards.