Filter use

[rowghani]

Hey guys so I have a general question about filter usage when making prints. A friend of mine taught me that as you move up the filters, more light will be blocked and therefore you have to increase your exposure. I don't really find this to be the case until I reach filter # 4. What are other people's thoughts on this? The jump from 3.5 to 4 seems to be almost always 1/8 or 1/4 of a stop for me.

 

[tedr1]

Yes there is a change for 4 and 5, double the exposure (if you are using the common Ilford type filters)

 

[grahamp]

That could be confusion with the two ways a colour head can emulate filters. The fixed grade filters do have a speed step above 3.5. I would think 1/4 stop is not enough, myself, but there may be other variables in the mix. Judge by results! It can appear that some filters are getting more dense, but the paper has different sensitivities to your eyes.

With colour head emulation of filters you can either match the colour only (variable exposure times), or match the colour and add some neutral density to get standard exposure times. Even then, most people accept the speed step at G4+ in the interests of shorter exposures in the more normal mid-grades.

Ilford do publish relative exposure details for their filters.

 

[pentaxuser]

Interestingly I noted last night that while my Ilford MGII filters seem to get denser ( more magenta looking) up to grade 3/3.5 the grade 4 filter is distinctly lighter and more yellowish looking and the increase in exposure is almost nothing. Grades 4.5 and 5 are more dense than 4 and again are magenta looking but do not appear denser than 3 or 3.5.

It may be that my grade 4 filter has faded badly but even the 4.5 and 5 filters add very little in terms of exposure as measured by my analyser's probe. Probably a similar increase to the OP. However it may be that the eye is deceived and double exposure is required.

Does anyone here still use MGII filters and if so can they say if their set is as per my description. Equally can anyone who has the latest set of Ilford filters confirm that they get progressively darker?

I do not want to hijack the thread but answers to my questions may be relevant to the OP, assuming of course that he too has Ilford filters.

It might help if he were to confirm that his filters are Ilford as well. It sounds as if they are Ilford but confirmation will help.

pentaxuser

 

[rowghani]

hey guys yup they are ilford filters and I have been given the recommendation to increase by a stop going from 3.5 to 4. thanks for all the responses.

 

[dpurdy]

I just bought a brand new set a few days ago and on the package it states:

ILFORD MULTIGRADE filters can be used above or below the lens...
The whole numbers correspond approximately to the contrast grades obtained with ILFORD graded papers.
Filters 00-3.5...........full speed (x1)

Filters 4-5................half speed (x2)

 

[Huub]

It could also be the case that your friend has some realy old filters, used for the Multigrade II paper. Those came with a calculation disk, which you used to recalculate exposure times when you changed filers. When Ilford Multigrade III paper was introduced somewhere in the early '80 s, the filter system was upgraded to the current system, which ask for a doubling of the exposure time when going from grade 3.5 to grade 4. When you still use those very old filters it could be an idea to upgrade to the newer system, also because the old filters are most likely to have faded in one way or another or contain other damages.

 

[MartinP]

It is a really wild idea, I know, but why not read the datasheet from the manufacturer?