Let's Talk Test Strips!

I'm wondering if people could share their methods for making test strips, those key guides to determining your base exposure for every print. For a while, mine have been remarkably poor in quality. At the moment, I cut a piece of 8x10 paper into about four pieces, so that they're 8"x2.5." I hold a piece of cardboard over my strip and expose each strip segment for an additional three seconds (using a digital timer). But I can never hold the cardboard steady or move it a consistent distance along the length of the strip. And if I get to close, I could end up touching the strip, leading to fuzzy double-exposures and ruining it. And even if it weren't ruined, it's hard to be sure you're reading the right time because the regions are so diverse in width!

So, I have a new method that I'm going to try. I bought some 1/2"-wide magnetic tape, which I plan on using to both hold down the edges of the strip and also gradually shield it from exposure. That way, I'll have strips that are pretty darn consistent!

So what method do you use for making test strips? Do you do three seconds per segment, or do you vary your times to make differences based on a logarithmic scale, such as stops of exposure? And finally, what criteria do you personally use to judge the "correct" time?

I place the strip in the easel and place a board on top of the strip for the first exposure, moving the board to the second position and so on. The board does not move the strip if it is placed on top, this is with a two bladed easel. Regarding F stop, I guess after so many years I simply know the starting point, usually F8 or 11. The F stop will largely be determined by the density of your negative, too much-too little you will need to adjust. Tim increments are usually dependent on the size print, but 8x10 to 11x14 usually 3-5 seconds with approximately 2" areas exposed. Then find the closest to what you are looking for and place a strip so that it includes a hilight and deep shadow and expose the entire strip. Adjust accordingly until you have detail in both. Print. Adjust. Print Again. I am sure others will have additional methods for you to try.

I use little strips of paper, about one-inch by two-inch. It is a little slow, but I do them one-at a time. It could take hours to work up a print before a full sheet gets in the easel. There is no way to know what changes need to be made to the next one until the first is dry. Trying some 'method' of exposing multiple little pieces at once just results in a big waste of paper, been there, done that.

I use 5x7 papers with an old Kodak Print template on top of it. The template has a pattern of various dark pie slices that give you timings if you shoot the whole thing for a minute. They I just pick the pie slices I like best and interpolate somewhere in between for my first straight print.

I usually use a whole sheet of paper, and judge the neg by experience and enlargement size. I may use slightly more paper than using strips, but I get to see the entire print and its relationships this way.

Edit: I also wanted to add that using Michael Smith's method (see his site) of outflanking/overshooting is integral to seeing what your neg has to offer.

Check out "Way beyond monochrome" for a good introduction to making f-stop test strips. I was an eye opening to me.
A few chapters are actually downloadable: http://www.waybeyondmonochrome.com/WBM2/TOC.html
See chapters on "Make your own test stip printer" and "Timing print exposures". Great stuff.

DELETED...

EDIT: anikin beat me to it, so I SECOND his suggestion!

Trust me, I am terrible with woodwork and I was able to build it successfully. It's not perfect, but it has absolutely made making test strips, both continuous and a single section, a piece of cake!

Mike

I make test strips from a sheet of 8x10 paper. I use a paper cutter and cut five strips two inches wide by 8 inches long. I set up my enlarger to make an 8x10 print, and from looking at my contact sheet decide where across the image to place the test strip. If its a portrait I'll include the face and background, if a landscape diagonally to get foreground and background and sky, etc. I mark the position on my easel with a piece of masking tape.

I place all of the test strips in a paper safe, and expose them on a time sequence based on the initial exposure of my contact sheet.
I develop all five strips at the same time in a large tray.

Sometimes I dry the strips with a hair dryer, but usually I can spot my exposure while the strips are wet.

Based on the test strip I then make a full size working print.

I'll chime in with a 3rd on the f/stop test strips, it' the way to go, really.
And kudos to Messrs Lambrecht and Woodhouse for a weighty tome for the
ages.

I also trust my metering/EI and will usually get a good starting
print by doing a test strip to detemine the minimum time needed
to get the unexposed edge of the film to print 'black'.

Without building 'test strip printer' you can get a fairly good result by
exposing a little more paper with each exposure, shown on the left.
The accumulated exposure will be in the right column, and are 1/2 stops apart.

exp - accumulated
------------------
02 - 02
01 - 03
01 - 04
02 - 06
02 - 08
04 - 12
04 - 16
08 - 24
08 - 32
16 - 48
16 - 60

FWIW I have made an f-stop template using Neutral Density (ND) gels/filters from a swatch book (either Lee - UK or Roscoe - USA). A .15nd is a half stop of reduced light; .3nd is 1 stop of reduced light; .6 is two; .9 is three and so on. I have a cardboard holder with these swatches mounted and I can "add" additional pieces of ND gel depending on how strong the enlarger light is on the baseboard - the variables being the height of the head and the stop on the lens. I tend to use only a stop of 5.6 as this seems to be my enlarger's lens sweet spot for sharpness. I expose the print thru the template with one base exposure of, for example 30 seconds. If the 1 stop (.3nd) looks to be the best exposure I half the base time while keeping the lens glued to the stop of 5.6. A stop of light reduction is half (-50%) the base time in seconds while a stop of light increase is double (+100%) the base time. Likewise, arithmetically, one can use the .15nd too for half stop increments and use a 50% increase or a 25% reduction. This might seem to be overly complicated but I am a retired motion picture chief lighting technician and have come to use this method over the years to do exactly this on film lights and on motion picture cameras. Hope that this helps.

cheers, sam

P.S. FYI you can also use this mathematical relationship when increasing of decreasing the height of the enlarger head if you have a ruler or scale on it's supports. Halving the height of the head increases the light intensity by a stop (or double if you will) and raising the head by doubling the height decreases the light by a stop (or 50%). The relationship holds true for all set heights but becomes a bit hard to calculate sometimes........this is how I calculate expose times for different sized enlargements.

I repeat from a post I made yesterday:

"I have a Saunders Colour Proofing Easel that does four identically cropped 4x5 test prints on the same 8x10 sheet - simple, elegant and no moving parts.

Admittedly it is a bit large, and sometimes a 4"x5" "strip" is awkward for tests, but I find it works really well.

I even have the instructions".

Each strip is exposed for a 1/2 stop more than the preceding one.

If I'm using split contrast printing, I'll use the same procedure for each of the soft contrast and hard contrast filter settings.

I've also used the "accumulating" test strip procedure referred to above.

By the way, if you are having trouble getting even sized strips, I'd suggest just dropping a ruler either on to your paper or the easel blades to serve as a quick guide.

I use a percentage method for making test strips. This is similar to f-stop printing but easier for me and my metronome (no timers for me, I can count seconds and watch my work instead of the timer...). With either percentage or f-stop increments, successive stripes receive the same proportion of exposure increase.

First, I like exposures in the 15-30 second range, so I choose an f-stop that I feel will get me in that range. This is often just a guess, but with papers I use a lot, I know from experience.

Before making the strip, I choose a paper grade for the strip based on the proper proof. If there is any doubt, I choose the lower contrast grade.

I normally use 1/3 to 1/2 a sheet of whatever size paper I'm printing on. Key here is to get a good cross-section of the important tones in the print (and not in areas you think will need dodged or burned). Sometimes I need a whole sheet to accomplish this, but smaller strips usually do the trick. The paper goes into the easel so it is held down on two or three sides to keep the strip from moving.

When exposing the test strip, I progressively cover the strip with a piece of mat board at the prescribed intervals. I count the base exposure, cover a strip with the board and count the next "strip time."

I like 20% strips (even though sometimes the stripes sometimes blend in together making it difficult to find the borders.... In this case, a 30% strip works). I feel it is important to have both definite under- and overexposure on the test strip, so I use a fairly long range of times.

For a roughly 20% test strip, I count as follows:

10 sec (minimum for me and usually markedly underexposed)
+2 (= 12 seconds; a 20% increase in exposure)
+3 (= 15 seconds; a 25% increase in exposure, rounded up from 2.4 sec)
+3 (= 18 seconds; a 20% increase)
+4 (= 22 seconds; about a 22% increase, rounded up from 3.6 sec)
+5 (= 27 seconds; about a 22% increase, rounded up from 4.4 sec)
+6 (= 33 seconds; a bit more than 25%, rounded up from 5.4 sec)
+7 (= 40 seconds; a bit more than 20%, rounded up from 6.6 sec)

This gives me 8 strips between 10 and 40 seconds. The order is easy to memorize (count ten for base exposure then 2, 3, 3, 4, 5, 6, 7) and repeatable.

For a roughly 30% strip I count:

10
+3 (=13 sec)
+4 (=17 sec)
+5 (=22 sec)
+7 (=29 sec, a bit more than 30%)
+9 (38 sec, a bit more than 30%)
+11 (49 sec, a tiny bit less than 30%)

Also, easily remembered and a wide range of times. (Some might find the 30% increments better to start with since the separation is easier to see.)

If my first strip doesn't contain enough usable information, I make a second, adjusting f-stop or light intensity, or moving from 20% to 30%, if needed to get the time range correct and adequate separation between stripes.

I should add that I judge proper exposure by looking for the desired values and separation in the lighter areas of the print (high-value placement) following the good old "expose for the highlights, change contrast for the blacks" rule.

I then make a straight print on a full sheet at the time I have chosen, dry it down and start the refining processes. If I feel I need a different contrast grade, I make a new test strip. This ends up saving paper and time in the long run.

I just use the strips to get somewhere in the ballpark. The real work comes in refining the print (exposure changes, developer tweaks, dodging, burning, flashing, bleaching, etc., etc.), but that's another story.

Best,

Doremus Scudder
www.DoremusScudder.com

Thats a great idea Matt. I have a Saunders print and repeat easel that allows eight prints on an 8x10 sheet with the appropriate mask, and using the X-Y axis movement on the easel.

I usally use a full sheet. Time is about 5 seconds each.

Jeff

Test strips are a waste of time

Full sheet, watch the whole image emerge in the developer
make your contrast and density judgment there, flick on lights for 5 seconds to verify your safelight call
move on.

toro_mike said:

Trust me, I am terrible with woodwork and I was able to build it successfully. It's not perfect, but it has absolutely made making test strips, both continuous and a single section, a piece of cake!

Mike

Click to expand...

I made mine out of cardboard, glue, and duct tape. It's not pretty, but it works very well. I second the f-stop method as well.

Also- for those less handy with tools, hobby stores (Hobby Lobby in the midwest) have a section with small pieces of thin birch plywood for very little money. I'm not sure what the hobby application is, but it would be perfect for this test strip printer.

I use a strip 3 - 4 inches wide, the length of the diagonal of the print size. I hold it in place with easel blades, and keep a small herd of shower curtain magnets (the little round flat ones that hold the curtain to the side of the tub) around the edges of the easel, and use them to hold down loose edges. I make sure that the strip passes through both an important shadow area and an important highlight area, or sky area, if relevant. I use a card to progress across the strip as others have mentioned, resting my hand on one side to keep the edge sharp. The bottom surface of the card is black to prevent reflective exposure from the paper. I just have a simple Zone VI timer, so I just choose a number (usually between 3 and 5) and make the exposures. If experience tells me what a minimum will be, then I start with that and add small amounts, as Doremus says above. If split filter printing, I do both filters and develop at the same time (the high filter is almost always a stop less). From there I go to full sheet, unless I feel like I need to test a split filter balance. The contact print tells me most of what I need to know about overall issues like burning and dodging.

I am paper waster. Usually I print sqare format and I cut piece about 1/3 of from paper to get base time for highlight. I rarely use test strips smaller than that.
If I am doing 30x30 cm print on 30x40 paper, I use strips of 10-15cm x 30 cm.
I relly need to get important parts of picture on the strip.
First that highlight strip wihth softest grade by using f-stop timing.

I put the strip on the easel, then use two pieces of ordinary cardboard to expose always one part of strip. Then I move the cardboards so that exposed part is covered and space next to it will give 1/3 stop more light.

I have really old and cheapish philips timer with 3 dials, one for 10 seconds, one for seconds and one for tenths of second.
Perhaps it sounds complicated, but after a while the time sequence for f-stop timing is easy to remember.

After i have found time for highlights, i use that time and do another strip with changing grade only.

Although with same two strips i could get basic times for split printing, i only use it occasionally. The old grade oriented approach seems to suit better for me.

Then some fine tuning strips... And first work print, more analysis and so on.

I've done it all at one time or another. Whole sheets, small strips. Kodak's print projection scale, piece of cardboard moved between exposures, etc.

When I got the RHDesigns timer a few years ago, test strips not only got easier, but became a revelation. F stops (IMHO) is the way to go regardless of how you do it.

From a mechanical standpoint, I solved the problem of the strip moving by tacking it down with a couple of small pieces of drafting tape. (Be sure to remove before sticking in the developer!) I also made some narrow clear strips with lines and times printed on them to use as a guide for the cardboard used to cover portions of the test strip, and as a readout of the exposure times (a la the Kodak scale). Old test strips have all been thrown away, or I could post one to show - 1 picture = 1000 words.

Depending on what the image size will be I give three seconds for each strip. Example for a large image printed on 11x14 paper will have six strips of exposure; 18, 15, 12, 9, 6, and 3. I use a large black matte board, 14x18 inch, and doubled in thickness. I set the timer for 18 seconds and moved the board every three seconds to my left exposing another strip until the whole paper have been exposed. It should be noted I use a Zone VI compensating time which allows me lower the intensity of the light so I can have better control of the test.

I love reading how everybody does their test strips. So much great information in here (and things I intend to try during my next session). Thanks to the OP for posting the question and thanks all for the wonderful answers...

Mike

Bob Carnie said:

Test strips are a waste of time

Full sheet, watch the whole image emerge in the developer
make your contrast and density judgment there, flick on lights for 5 seconds to verify your safelight call
move on.

Click to expand...

I'm with you on this one, Mr. Carnie. I use half sheets (of 11x14 paper), eyeball it for a given density and move on from there. I usually have it close by the third piece. I tried test strips by they don't agree with my brain. I rather make the call from the complete image.

I use a sheet or strip large enough that every segment will have both highlights and shadows.

Turn on the light, and count while progressively covering the paper.

I cover the first sector after 4 seconds, then 5 1/2, 8, 11, 16, 22, 32 and 45 seconds.

The first is almost white, and the last almost black. but there is a half stop between each segment, so if the correct exposure should have been 22 seconds, i can open half a stop and expose at 16 seconds, or a full stop and expose at 11 seconds, or close down in the same way to get 32 and 45 seconds.

This also tells me if I should use a harder or softer grade to get the mid-tones I want - if the steps are too easy to see it's too hard, if the changes are too week it's too soft.

I can appreciate how some may consider test strips a waste of time, especially if you've got a good handle on your printing process. Unfortunately for me, I started with a digital camera, and I've only been shooting film for the past year. In fact, I've been in the darkroom for only a few months! So while I get the hang of the darkroom, I'll probably want to stick to test strips while I work on getting a "feel" for printing.

In particular, I've liked the notes from Ole regarding determining the correct contrast grade, and samcomet regarding the relationship between stops and height of the enlarger.

At present I use a Kodak Projection Print Scale to determine the center point for making the standard test strip. http://www.flickr.com/photos/kb1awv/5357450760/

For example, if the Projection Print Scale reveals that after dry-down an exposure of 28 seconds would be a good general exposure I then make a normal test strip (card pulling) with set intervals above and below the 28 second exposure. ie; 24, 25, 26, 27, 28, 29, 30, 31, 32 seconds. These test strips eventually end up in a file folder w/notes for that print.