All About Ilford FP4

Ian-Barber

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I have just been watching this video describing all about FP4+
He goes on to mention that if you use a Green filter with this film, then you are probably going to end up with a flat image.

Has anyone experienced this.

He mentions about the flat image when using a Green Filter at position 28:00

 

Ian Grant

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He doesn't really know what he's talking about and hasn't a clue about ISO speeds.

He states that the speed as 125/22 and the 22º is the DIN (German) speed which is correct but the 125 is more correctly the ASA/BS standard, the International Standards Organisation allows the speed to be measured by the ASA/BS method or the DIN and there's an agreed conversion. He's not read the Ilford FP4 Plus datasheet which specifically states "FP4 Plus has a speed rating of ISO 125/22º (125ASA, 22DIN, EI 125/22) to daylight".

Where he's wrong is stating the 22º is not an ISO standard it's one component. Kodak had the American ASA film speed standard changed and relaxed when they released TMax 100 & 200 because the films couldn't reach their nominal box speeds using the proscribed ASA testing routine which required a specific developer. Kodak were able to have the standard changed because there were no US competitors making B&W films.

It's often forgotten that films have two ISO speeds, one for Daylight and the other for Tungsten, FP4 had a Tungsten speed of 80 ISO, at one time many photographers used Tungsten studio lighting so this was once important but has been dropped in more recent years. Ilford still list a Daylight and Tungsten speed for their Ortho sheet film, it's primarily a copy film and traditionally copy lighting has been Tungsen.

Adox and later EFKE actually used the Tungsten Speeds on their film names Kb/R/Pl 14, 17 and 21. These were of course the DIN speedsas Adox was a German company later taken over by DuPont. EFKE eventually renamed them with their ASA speeds Kb/R/Pl 20, 50 and 100.

The filter factors given for Green filters are specifically for films like FP4 and Plus X, Hp5 and Tri-X, I've never had flat images when using a Green filter with FP4, but I wouldn't use one in tungsten light either :D

Ian
 

Stephen Batey

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Registered User
I haven't yet watched the video, but I haven't personally noticed any flat images with FP4 when using a green filter (which I often use for landscapes and trees). I use both a light and a darker green. As in Ian's case, these are daylight exposures.
 
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