how do you use contrast filters?

uginz · 18th September 2006

I'm a little lost with this.

say the enlarger bulb defalt is grade 3.
but it want a 3 1/2.
do i use a 1/2 filter or a 3 1/2 filter?

in a nutshell, are the filter numbers additive? eg 3 + 1 = 4?
or
watever filter number you use will override the bulb's number?

Ansel · 19th September 2006

Actually "standard" enlarger bulb is grade 2, as is "standard" paper. They are supposed to give you normal contrast. So grade 2 no need any filter. But you will have to test it for the particular paper, enlarger combination in your environment.

When you need a grade 3, you slot in a grade 3 filter. When you need grade 5, you slot in grade 5. You are aware that increasing grades means increasing contrast right?

Now lower grades, ie those below 2, are for decreasing contrast. They are of different colour tones. This is how multigrade paper work. They are designed to respond differently to different tones of light. That is why if you have a colour head enlarger, you can actually use the colour controls to "dial-in" the contrast you require.

I don't think you are supposed to stack those filters together. I am not sure if you stack all the different filters together will give you any funky effects or not.

uginz · 20th September 2006

thanks.

another question, when using filters, is it's normal that exposure times also increase?
seems logical that exposure times increase as you now have a filter that blocks some light.

Ansel · 20th September 2006

Originally Posted by uginz

thanks.

another question, when using filters, is it's normal that exposure times also increase?
seems logical that exposure times increase as you now have a filter that blocks some light.

yes, you are right. Test until you get it right.

18th September 2006	#1
uginz Member Join Date: Feb 2004 Posts: 346	how do you use contrast filters? I'm a little lost with this. say the enlarger bulb defalt is grade 3. but it want a 3 1/2. do i use a 1/2 filter or a 3 1/2 filter? in a nutshell, are the filter numbers additive? eg 3 + 1 = 4? or watever filter number you use will override the bulb's number?

19th September 2006	#2
Ansel Senior Member Join Date: Apr 2003 Location: Land Downunder Posts: 2,069	Re: how do you use contrast filters? Actually "standard" enlarger bulb is grade 2, as is "standard" paper. They are supposed to give you normal contrast. So grade 2 no need any filter. But you will have to test it for the particular paper, enlarger combination in your environment. When you need a grade 3, you slot in a grade 3 filter. When you need grade 5, you slot in grade 5. You are aware that increasing grades means increasing contrast right? Now lower grades, ie those below 2, are for decreasing contrast. They are of different colour tones. This is how multigrade paper work. They are designed to respond differently to different tones of light. That is why if you have a colour head enlarger, you can actually use the colour controls to "dial-in" the contrast you require. I don't think you are supposed to stack those filters together. I am not sure if you stack all the different filters together will give you any funky effects or not.

20th September 2006	#3
uginz Member Join Date: Feb 2004 Posts: 346	Re: how do you use contrast filters? thanks. another question, when using filters, is it's normal that exposure times also increase? seems logical that exposure times increase as you now have a filter that blocks some light.