Fixing and other starnge thoughts

[Tony]

Is there a relationship between fix time and water rinse time?
Or I am thinking about this all wrong?
Bare with me.

So say it takes a plate 15 seconds to clear (AmDi) in fixer and another plate 45 seconds to clear. Maybe the only difference is age all the rest is even.

Going into the water bath, are they the same hardness?

If fix time is say 15 seconds should the water rinse is also less than one that took a minute?

Is fix time a good indicator of hardness? Is a fast clearing time in fixer mean the film not very hard?

Thanks,
Have a good weekend all
Tony

[Johnfp]

I actually answered every question then started over.

Yes, you are waaaayyy overthinking this. Keep fix time and water rinse time constant. There is enough other stuff going on. But if you want answers just to know, I will be glad to give you my opions.

Read "Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light" The discussion section near the end is increadible about CR states and what light and chemicals do to it. It would pretty much answer those questions for you. Jeff's got it dowwwnnnn!

[Dinesh]

Is there a relationship between fix time and water rinse time?

Yes. The harder the plate, the more you need to soak. If you doubt that, leave a plate in for a minute or so and leave another one in all night. Then soak them the same amount.

So say it takes a plate 15 seconds to clear (AmDi) in fixer and another plate 45 seconds to clear. Maybe the only difference is age all the rest is even.

Going into the water bath, are they the same hardness?

Depends on the age and constitution of the fixer. But, in general, no they're not the same hardness.

Is fix time a good indicator of hardness?

Depends on the type of fixer and it's age and also the type of plate and it's age. In general, yes.

Keep fix time and water rinse time constant.

No. The relationship is not linear. "Hardness" refers to the density of the plate. However, the holographic parameters are dependant on the index of the plate. This translations occurs via the Kramers Konig relationship, which is almost - not quite - linear. So, doubling the fix time does not infer doubling the water rinse time. It also depends on the pH of the water. To check this, put a plate in for 1/10th of your normal fix time, then soak it for 1/10th of your normal wash time. Do the same for a plate put in the fix for 10 times your normal fix time, ie wash it 10 times your normal wash time. If the (fix time/water rinse) = constant, there should be no difference between plates.

[Johnfp]

Dinesh, you misread. I didnt say they keep them the same, I said keep them both constant. In other words do a 2 min fix and a 5 min wash and don't change those variables.

[Dinesh]

Dinesh, you misread. I didnt say they keep them the same, I said keep them both constant. In other words do a 2 min fix and a 5 min wash and don't change those variables.

OK, I think we misinterpreted the word "constant". To me it means that the relationship between the two is constant. So, my interpretation of Tony's question was, "If I went from 2 minutes in the fix to 4 minutes in the fix, how does that alter the wash times.' To which, my answer is that two minutes doesn't usually harden by twice as much, so you don't need to wash for twice as long. If I (with my chemicals and processing scheme) went from 2 minutes in the fix to 4 minutes in the fix, I'd increase my wash time from 5 minutes to about 8 minutes, not 10.

[Tony]

Yes, you are waaaayyy overthinking this. Keep fix time and water rinse time constant. There is enough other stuff going on. But if you want answers just to know, I will be glad to give you my opions.

I have to disagree with you on this one John. Fix time is another tool for color tuning and brightness control. I am questioning weather rinse time can effect outcome based on fix time. If the hardness (density may be a better word) is less than I am wondering if rinse time should be varied.

No. The relationship is not linear. "Hardness" refers to the density of the plate. However, the holographic parameters are dependant on the index of the plate. This translations occurs via the Kramers Konig relationship, which is almost - not quite - linear.

Yes this is what I was wondering.

But, in general, no they're not the same hardness.

So if this is true then rinse time can have an effect. Can less harden plates run the risk of having gelatin removed?

Thanks guys!!

[Tony]

Never heard this before.
Pretty cool
Nice job John (Jeff)

http://river-valley.tv/improving-the-re ... ser-light/