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Thursday, March 03 2005, 7:38 PM
HP5+
Well the last few days I have been involved in testing my proper index and exposure for HP5+ film and it has been quite a battle. I have gone through two 25-sheet boxes to nail this film down. I started testing with a dilution of HC110 of 1:31 which gave me a proper development time of 4 minutes for normal but the problem was that I needed a development of at least 6 to 7 minutes for N- development without the time dropping down below 5 minutes.
I decided to recalculate my dilution and tried 1:64. The only problem with this was the film base reading was completely off, so I figured that the dilution was too much and acted more like a water bath, as the base reading was .05 on the densitometer. The 1:31 base reading was .11, which was to be expected. At .05 at the 1:64 dilution, I was afraid that shadow detail would be lost, so after wasting another 8 sheets, I recalculated to a dilution of 1:45 which gave me a base of .11, so I knew this dilution would work and hold shadow detail.
After all this trial and error I finally derived at my index and development time for HP5+.
Finally nailed it and in the process so much was learned! Now, that is the best part, knowledge.
My findings with HC100 diluted at 1:45 at 68F (20C) for 6 minutes gave me the following readings.
Index 200
Zone 1 - .11
Zone 8 - 1.25[SP
6 minutes 30 seconds for zone 8 read 1.36
So I will process this film at 6 minutes 15 seconds. That should get me 1.3.
Finally nailed it and now I am ready to go and shoot! Just ordered two boxes of 100 sheets! Yes!
* Testing was done with a JOBO CPE-2 with a 5-minute pre-rinse and a 1-minute water stop bath.
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Part Two
Process for zone testing;
I will use a box speed of 400 for example. You need to test for z 1 to get your index and z 8 to get your development time. For z 1 you are looking for a value of .10 to .12 on the densitometer and for z 8 a value of 1.3.
So the test ran like this;
1/30th @ f11 ISO 400 was my zone 5 reading.
* ISO 400 z 5 f11 close down to z 1 = f45
* ISO 320 open 1/3 f32 2/3
* ISO 250 open 1/3 f32 1/3
* ISO 200 open 1/3 f32
Now we will shoot a corresponding zone 8 exposure.
1/8th @ f22 ISO 400
* ISO 400 z 5 f22 open to zone 8 = f8
* ISO 320 open 1/3 f5.6 2/3
* ISO 250 open 1/3 f5.6 1/3
* ISO 200 open 1/3 f5.6
I then loaded the sheets into the drum processor and processed the film. This is repeated until you nail it!
If your index (zone 1) for example is .05 you need to increase you ISO so if 400 gave you a .05 reading you need to go to 320, 250, 200, 160, 125, etc until you find a reading of .11. If your initial reading was more than .10 you need to decrease you ISO, so from 400 you would go to 500, 640, etc until you reach the .10 mark.
For matching zone 8 you will need a value of 1.3.If you are > 1.3 decrease the development time and it you are < 1.3 increase you development time. Once you find this you have completed the test!
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