Test Strip for Large Print

RedSun · Jan 27, 2020

When you print large B/W with enlarger, do you use test strip from the same paper box? For paper like 11x14 and 16x20, the test strip from the same paper can be costly. The paper comes in 10, 25 and 50 pages box.

Also, after the paper box is opened, how stables are the B/W papers over time? Mainly talking about multi-grade papers.

MattKing · Jan 27, 2020

Yes you need to use paper from the same box. It is a good idea to devote your first sheet from the box to test strips - maybe even put portions of the sheet into a smaller envelope in the box.
Paper is quite stable if the humidity and temperature is maintained at a reasonable level.

RedSun · Jan 27, 2020

MattKing said:
Yes you need to use paper from the same box. It is a good idea to devote your first sheet from the box to test strips - maybe even put portions of the sheet into a smaller envelope in the box.
Paper is quite stable if the humidity and temperature is maintained at a reasonable level.

This is what I do with paper printing, but mostly in 8x10 and it comes in like 50 sheets a box. It is hard to cut a 16x20 sheet from a pack of 10 sheets.

I have a LPL VCCE head. But I figure it still does not eliminate the need for test strip.

How the lab does it? Use density meter to measure both contrast and density to get the correct exposure?

MattKing · Jan 27, 2020

RedSun said:
How the lab does it? Use density meter to measure both contrast and density to get the correct exposure?

That and a fair bit more.
When I used to work in a lab printing proofs and machine enlargements (for wedding and portrait and commercial photographers) the Durst machine printer I worked on had both a built in analyzer and a test strip mode. I would take the rolls of film and run each one through the test strip mode. The machine printed on to rolls of paper, each several hundred feet long. The test strips created from that mode were angled trapezoids showing the middle of each image - each one the same width as the paper roll. I would run 10 - 30 rolls through, with each frame advanced by hand. All of those test strips were printed sequentially on the same strip of paper, one after another, and that strip was than cut and fed through the roller transport RA-4 paper developing machine which worked dry to dry - unprocessed roll paper in, and processed and dried paper rolled on to a core at the other side.
I then took the results, cut them to pair the test strips with the appropriate films, and then proceeded to evaluate each test strip for the necessary correction (if any) for density, magenta, cyan and yellow. Those corrections were, of course, from the settings coming from the built in analyzer.
I would write the necessary corrections on the strips themselves with a grease pencil.
The machine was then switched to the full size print mode, and each negative was analyzed and printed again, but this time with the added manual corrections resulting from my evaluation.

bernard_L · Jan 28, 2020

RedSun said:
It is hard to cut a 16x20 sheet from a pack of 10 sheets.

But how many of these 10 sheets would be lost because of improper exposure, resulting from inadequate test strip (too small, from a different paper batch...) Plus, you don't need to "waste" one full 16x20 in test strip. Maybe you can set aside one 12x16" for a print to be gifted to a friend, and cut the rest of that sheet into test strips?

darkosaric · Jan 28, 2020

I cut one big paper in like 8-10 equal parts, put them in another small box, and use them for test strips. Usually when I print - many prints that I do in one session are form the same camera and same film type (from the same trip), so that reduces test strips usage a lot.

Hilo · Jan 28, 2020

Always use the same paper for test strips. Unless you have more boxes or envelopes with the same badge number. You find this number on the label. For the same paper, between different emulsions (batch numbers!), there can be significant differences.

I do a lot of 20X24" printing and, for tests, will most likely use one sheet of paper on every 10 sheets. Sometimes a bit more, sometimes a bit less. I never see it as a waste, it is part of the print.

Rudeofus · Jan 28, 2020

A long time ago, there were some very cheap papers around, made by companies with obsolete and inadequate equipment. These papers may have been beautiful, but they were different from batch to batch. You would dial in a print perfectly with test strips cut from a box of 13x18cm sheets, only to get very disappointing results with a 30x40cm sheet. At least that's what people reported back then.

These days I constantly make test prints on 9x13cm paper, and then use the corresponding exposure on larger formats. Note, that you absolutely have to do your final contrast&exposure tests at the magnification you want. If you make the enlargement bigger, you not only change contrast, but you inadvertently also change contrast, which can lead to nasty surprises.

RedSun · Jan 28, 2020

Some of the VCCE head says the exposure time won't change with different contrast grade. Is that accurate? Or need test strip too to confirm it?

koraks · Jan 28, 2020

RedSun said:
Some of the VCCE head says the exposure time won't change with different contrast grade.

That cannot be the case as papers are different in this respect. Verify with a test strip.

MattKing · Jan 28, 2020

RedSun said:
Some of the VCCE head says the exposure time won't change with different contrast grade. Is that accurate? Or need test strip too to confirm it?

It is sort of accurate.
In most cases, it is best to key your exposure on a light mid-tone or low highlight tone, and then to modify your prints from there.
The variable contrast papers are designed to be "speed matched" when used with a light source or manual table that is designed to mix a combination of filtration - both magenta and yellow (or green and blue with some systems) - in a particular way.
All that means is that for each type of paper there is a particular tone - again a light mid-tone or low highlight tone - for which changing the contrast settings will give you the same tone without changing exposure. The other tones - highlights, mid-tones and shadows - will all change as you change the filtration.
If you change filtration, the speed matching means that when you do new test strips you probably won't need many - you can centre your times around the time that worked well with the old filtration, and you can use smaller increments of time, because the speed matching will result in the new tests being quite close to being right.

pentaxuser · Jan 28, 2020

Redsun, this will sound like a bit of heresy from me now that you have the opinions above but my understanding is that if it is the same paper and surface say Ilford MGIV RC Pearl still equally fresh then projecting a 16x20 image but using a 5x7 paper to cover an area of the projected negative that gives you a good range of zones should not result in much if anything of a difference than using a large piece of paper from the same 16x20 box which you cut to size

I get the impression from what you say that you want to avoid the difficulty of cutting large paper or spoiling a large sheet by cutting it. If it were me then I'd use the same make of paper( assuming the sheets were fresh ) but use smaller sheets for the test strips.

I might just be more easily pleased of course but my understanding is that provided it is the same paper type then there should not be enough of a difference to make a noticeable difference

pentaxuser

Rudeofus · Jan 28, 2020

RedSun said:
Some of the VCCE head says the exposure time won't change with different contrast grade. Is that accurate? Or need test strip too to confirm it?

There is exactly one point in the exposure vs. contrast chart, which won't change with contrast changes. If that one point covers the most significant part of your image, then "exposure has not changed". If the most important parts of your image are brighter or darker than this one point, then exposure will obviously change, regardless of what the paper packaging or the enlarger head may say.

Note, that several papers openly state reduced sensitivity at higher grades, which means, that this "exposure doesn't change" point may shift as you progress the gradation scale.

Doremus Scudder · Jan 28, 2020

Tests strips are your friends and they save paper.

Ideally, a test strip would be made from the same paper being used to make the print since papers can vary from batch to batch. I'll cut a piece of large paper into three or four strips lengthwise (three for 11x14, four for 16x20, etc.). I use my proofs to determine a starting contrast setting/grade and make a strip. I base my exposure on highlight values, so I'll find the strip with the highlights I think I should start with and look carefully at contrast. If I think the contrast needs changing, I'll make a rather large change and make another test strip. I can often then extrapolate a starting exposure if the contrast I want is somewhere between the two strips. I'll then make a first full-size print, which 99.99999% of the time gets thrown away, but is close enough that I can determine which changes and manipulations I need to make for the subsequent prints. I'm happy if I get a final print by print number three.

All that said, I can see using the exact same paper in a smaller size for test strips as long as the paper is fresh and from a manufacturer with good quality control and consistency (so the batch variance is minimized), e.g., using a couple of strips from an 8x10 sheet strategically placed when making a 16x20 or 20x24 print. The first straight print is just another test and gets tossed anyway, so that might save paper in the long run. A comparison between sizes shouldn't be hard to make quickly.

Best,

Doremus

RedSun · Jan 28, 2020

Here is from the Saunders/LPL VCCE that I have:

VCCE stands for "Variable Contrast, Constant Exposure." The
VCCE module is ideal for use with variable contrast papers since
you just dial in the desired contrast - exposure time and lens
aperture settings remain constant as contrast settings are
changed. No exposure recalculation is required. The VCCE module
has two channels to match the slightly different requirements of
Kodak Polycontrast III RC (and other compatible papers), and Ilford
Multigrade III RC (and other compatible papers.) You can quickly
switch between channels by means of a simple slide switch on the
front panel. The module also has a convenient "White Light
switch," which temporarily removes all filtration to maximize light
output for focusing and image composition.

I think it is all relative. VCCE should help to get the correct quicker than with regular color head or condenser head with color filter.

MattKing · Jan 28, 2020

RedSun said:
Here is from the Saunders/LPL VCCE that I have:

VCCE stands for "Variable Contrast, Constant Exposure." The
VCCE module is ideal for use with variable contrast papers since
you just dial in the desired contrast - exposure time and lens
aperture settings remain constant as contrast settings are
changed. No exposure recalculation is required. The VCCE module
has two channels to match the slightly different requirements of
Kodak Polycontrast III RC (and other compatible papers), and Ilford
Multigrade III RC (and other compatible papers.) You can quickly
switch between channels by means of a simple slide switch on the
front panel. The module also has a convenient "White Light
switch," which temporarily removes all filtration to maximize light
output for focusing and image composition.

I think it is all relative. VCCE should help to get the correct quicker than with regular color head or condenser head with color filter.

The Ilford Multigrade filters - both below the lens and above the negative types - are speed matched in the same way as your VCCE heads.
And the paper manufacturers include charts showing how to set colour heads to obtain the same result.
I use a 45+ year old Ilford Multigrade head and controller that works in a manner similar to the Saunders LPL VCCE module.
Your light source is high quality and convenient to use, but it will give you the same results as any other method of speed matching - ie. it will get you close and cut down on how many additional test strips you need to do.

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