Exposure change for new enlargement:
(      /      ) ^ 2 x  = 
( New Length / Original Length ) ^ 2 x Original Time = New Exposure
Exposure change by f/stops:
 x (2 ^    ) =   
Original Exposure x (2 ^ Number of Stops) = New Exposure
Dilutions:
 @ 1 +      =      : 
Volume @ 1+Dilution = Stock : Water
Percent Solutions:
Stock A Strength            Stock A Quantity 
Required Strength 
Stock B Strength            Stock B Quantity 

Filter Settings:


Y:   M:
Y & M filtration for Paper, Enlarger, Grade selected
Centigrade and Fahrenheit conversions:
DegC=  DegF 
DegC = (DegF - 32) x 5/9
Grams, Grains and Ounce conversions:
grains = grams = ounces
grains x 0.0685 = grams = ounces x 28.35
Millilitres and Fluid Ounce conversions:
fl.oz (uk) = ml = fl.oz (us)
fl.oz (uk) x 28.4 = ml = fl.oz (us) x 29.6
Litres and Gallon conversions:
gallons (uk) =  l =  gallons (us)
gallons (uk) x 4.55 = l = gallons (us) x 3.79