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DR Shout
Joined: 17 Jun 2004
Posts: 11
Location: Savannah, GA
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 Posted: Thu Feb 02, 2006 1:57 am Post subject: NEED RT Formula... can't remember |
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I'm looking for the formula for changing Density of film. I've always been a fan of making exposure charts, but now I'm in need of the quick fix formula of changing the time after an initial exposure to get the density I need.
Your help is appreciated...
Don |
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expatriatedamericanus
Joined: 07 Feb 2006
Posts: 11
Location: Saudi Arabia
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| Posted: Tue Feb 07, 2006 10:30 pm Post subject: Formula for Density |
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Copy and Paste this formula into the B9 cell in Excel:
$D$1 being the density desired.
$E$1 being the Initial Density.
1.21 is a constant and $F$1 is old time or
MAS.
This formula will give you your new time or MAS.
=(($D1/$E1)^1.21)*$F1
Then enter the values in the appropriate cells (D1, E1 and F1).
You can enter them in any row as long as the cell numbers coincide.
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DR Shout
Joined: 17 Jun 2004
Posts: 11
Location: Savannah, GA
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| Posted: Wed Feb 08, 2006 6:11 am Post subject: Thanks |
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That's great !!! I'll keep this on my computer.
Would you happen to know the by hand formula ? I'm trying to get this for a friend that is going to work in the field. I use to have this small booklet with all the x-ray formulas, but I lent it out and now it's MIA. |
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jerry6004
Joined: 20 Dec 2005
Posts: 2
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| Posted: Wed Feb 08, 2006 3:00 pm Post subject: Shot time |
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| is the shot time in minutes or seconds?? |
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expatriatedamericanus
Joined: 07 Feb 2006
Posts: 11
Location: Saudi Arabia
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| Posted: Sat Feb 11, 2006 4:34 am Post subject: |
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| Its the same as that exept I forget what the symbol ^ means in Excel. If you can fugure that out the formula will work on a hand calculator. Give me your email address and I will send you an Excel file with numerous calcs for UT & RT. |
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expatriatedamericanus
Joined: 07 Feb 2006
Posts: 11
Location: Saudi Arabia
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| Posted: Sat Feb 11, 2006 6:20 am Post subject: RT Formula |
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It means raised to the power of.
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DR Shout
Joined: 17 Jun 2004
Posts: 11
Location: Savannah, GA
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| Posted: Wed Feb 15, 2006 11:45 pm Post subject: |
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| It's in MAS. |
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DR Shout
Joined: 17 Jun 2004
Posts: 11
Location: Savannah, GA
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| Posted: Wed Feb 15, 2006 11:45 pm Post subject: |
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| My e-mail address is.... dshout@comcast.net |
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DR Shout
Joined: 17 Jun 2004
Posts: 11
Location: Savannah, GA
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| Posted: Mon Feb 20, 2006 7:00 am Post subject: |
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| Thanks for the programs !! |
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JWasiJR
Joined: 25 Mar 2005
Posts: 14
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| Posted: Wed Mar 08, 2006 5:12 pm Post subject: |
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| A good field formula is SHOT TIME times DESIRED DENSITY divided by DENSITY OBTAINED WITH TEST SHOT equals CORRECTED SHOT TIME. Remember to use seconds, or minutes only not a combination of both. Example....you have a density of 1.85 and want a 3.0. Shot time was 25 seconds. 25 sec X 3.0 divided by 1.85 = 40.5 seconds. Works every time.......... but only if you are running film thru a processer or manual developing using a time and temperature chart. Does not work with sight developing. Hope this helps you out. |
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DR Shout
Joined: 17 Jun 2004
Posts: 11
Location: Savannah, GA
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| Posted: Tue Apr 25, 2006 9:27 pm Post subject: Thats it... |
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| Thanks JWasiJR. I knew there was a simple formula, now I have one for the lab and a quick one for the field ! |
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