This is similar in nature to Warner's question. I recently watched someone make a test print by using a 0 filter and step-exposing horizontally on an 8x10 sheet of paper, then using a 5 filter and step-exposing vertically. The end result was a grid of varying exposures and contrasts. I maintain that this process is probably only useful for negatives that have relatively uniform tonalities throughout. For a complex landscape that may have large areas of shadow in one area and brighter sky in other areas this process won't work. Further, this sounds like a proceedure developed to allow a photography writer to sell an article and a photography magazine to sell subscriptions. I've taken a number of workshops and read numerous articles on the proceedures used by master printers and no one works like this. Any comments?

-- r (ricardospanks1@yahoo.com), June 11, 2001

Answers

Kind of a neat idea, but making test strips by any kind of step means can have a big error source. I recently made some calibrated step tablets by progressively covering the paper strip and making multiple exposures based on the measured paper curve. The results were *way* off. There's a well documented photographic effect that says the cumulative effect of multiple exposures will be less than a single exposure of the same energy. I hadn't realized how large this problem can be, and my final exposure series was probably a full stop more than I would have predicted. I then remembered that "stepped" test strips have never worked well for me in the past, and that was probably the reason. Now I do single exposure test strips and it usually takes very few to home in on the right exposure. Contrast is a matter of judgement and experience, but I don't find test strips of much use for that anyway.

-- Conrad Hoffman (choffman@rpa.net), June 11, 2001.

This is part of the "split filter" printing technique. The idea is that you expose the highlights using a 00 filter, and expose the shadows using a 5 filter. The grid you mentioned lets you pick the time for each filter. Once you have the two times, you use a 00 filter first, then change to a 5 filter and make a second exposure. I think the jury is still out if this really makes any difference than a single filter exposure. Some people says it's easier to think in this method. A web search should turn up a few dozen references for "split filter printing".

-- Dave Mueller (dmueller@bellatlantic.net), June 11, 2001.

When making a test strip or print, why would you not duplicate the test exposures? Conrad has pointed out that six 5 second exposures do not equal one 30 second exposure. If the best result is six 5 second exposures, make six 5 second exposures.

It helps a bunch if you do a little thinking before planning a test strip. If there are strong highlights and deep shadows in the same negative, plan your strips so that the minimum exposure falls in the shadow area and the maximum exposure falls in the highlight area. Then your base exposure can fall in between the two, and you burn and dodge to get the required results.

-- Joe Lipka (JoeLipka@compuserve.com), June 11, 2001.

You may want to read The Variable Contrast Printing Manual by Stephen Anchell. It covers split printing in great detail. As mentioned above, there are a number of good sites on the web with this information as well. As far as test strips are concerned, I use them to see which exposure and contrast give me the best overall print. I then fine tune fron that point on.

-- Jim Billups (jim@jimbillups.com), June 11, 2001.

I do test exposures with 1-2" squares of paper, one exposure per square. I can place them in selectively in highlight, shadow, face areas, etc. In a highlight area I'll sometimes place a paper clip on the paper during exposure to get a reference full white.

-- Tim Brown (brownt@flash.net), June 13, 2001.

Ricardo

I have never been a fan of the stepped test strip. FWIW here is how I do it. I set my head at grade two and establish what I condsider to be the most important hightlight. I then cut a sheet of paper into portions and make a series of exposures at half stop intervals. I do this by altering the time not the lens aperture. I then develop them together making sure I give them the full development time. Having washed and dried them I determine what I beleive to be the correct exposure. I then make a work print using that exposure and examine the shadows. If they are not rich enough I increase the contrast. If they have blocked up I reduce it. This combination of exposing for the highlights and setting contrast for the shadows works for me. I can usually get the base contrast and exposure time pegged down within 3 sheets.

Adrian

-- Adrian Twiss (avtwiss@ukonline.co.uk), June 14, 2001.