Jorge,
How accurate do you think it would be with pyro?
Jorge,
How accurate do you think it would be with pyro?
I have used it with ABC and now with Pyrocat and I get very consistent results. For best results you have to standarize and make your development tests with this timer at diferent temperatures to see if it is giving you best results, specially if you fiddle with the temp setting. The timer is very consistent, Jobo makes one too, but I bet it is outrageously expensive.
Bottom line the % adjustment seemed to work very good with ABC and Pyrocat. YMMV.
Do you have a Zone VI timer?
--Jorge, 2004-10-29 22:44:41
Hi Jorge,
I have one bought from Zone VI, I think 9 years ago and still working fine..
Jacques
For film development, I always just get the soup to the right temperature.
For paper, I compensate, but I do it based on tests that I've done in the past. The developers that I use are radically different in how they respond to temperature. The main difference is that Metol and phenidone respond in a pretty linear way to temperature over a wide range; hydroqhinone does not. It has a much steeper curve, and then plummets at lower temps. It's basically innert at 50 degrees (and this can be in issue when you live an print in a loft in 100+ year old brooklyn factory). The difference between a meol-only developer and a metol-hydroquinone developer are not subtle.
Testing is actually easy, because there's a direct relationship between the emergence time of an image and total developing time. You can work with a consistently exposed gray swatch, and note its emergence time at 68 degrees in one developer. From that point you can do the same thing in one or two degree increments above and below, however far you think you'll need. From this information you can extrapolate the total deveoping time for each temperature. If the emergence time is 10% longer at 65%, then you know the total developing time is 10% longer too. Repeat for whatever other developers you use.
I made a little chart for each developer I use. The leftmost column has the actual developer temp; the next columns are headed with various "normal" developing times that I use at 68 degrees ... like 1 minute, 1.5 minute, 2 minutes, etc..
In the boxes of the chart are the adjusted devoloping times. After one annoying afternoon of testing, I was done. Using the system couldn't be easier. I typically use two tray development (a low and a high contrast developer), so this means two charts above my trays. I recheck the temp a couple of times over the course of a long printing session to make sure things haven't changed.
Here's why this degree of accuracy can be important: I found that untoned prints would often look identical despite slight differences in developer temperature, but the differences would become pronounced after toning. Especially with nelson gold toner, which I use most of the time. With the correct amount of development, I get a nice cool brown. If there's too much development (from the soup being too warm) the toner gives a red brown. If there's too little development (from cold soup) I get inconsistent toning, including ocasional split toning. Tightening up the temperature/time controls completely eliminated the inconsistencies and a whole lot of grief. I don't believe it would be possible to get the same level of accuracy from a compensating timer that treats all developers equally.
<<I was looking at the Calumet site today and I noticed they are selling the Zone VI Compensating developing timers again....>>
Now if they would bring back the 120 rollfilm loader...
Ron
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