paul_hoyt

Are you asking about color compensating filters for color film, or are you using "black and white" contrast filters on color film? The FF on B&W contrast filters are for panchromatic B&W film; and the spectral characteristics of B&W film is different from color . They were not intended to be used on color positive or negative film. That doesn't mean you can't use them for artistic purposes. Checking the exposure with and without the filter on a hand held exposure meter will get you in the ballpark for the amount of light the filter is with holding. But the effect will be an overall hue of color you are shooting through, but I am sure you know that since it appears you have already done this.

You raise an interesting question. I was taught that the "filter factor" is applied to compensate for the loss of exposure due to the amount of light cut by the filter. It has been said that the factor should be increased or decreased depending upon the time of day [the Kelvin of the light] and the type of filter being used. Early morning and late afternoon tend to be less blue than mid day; you can decrease the FF with blue cutting filters.

Rodeo_Joe, Your logic reminds of the old math conundrum from the 1940's. Three men are traveling together and need to find a room in a small town. The only motel in town has 1 room left to rent. The clerk says that the room rents for $30.00 he can add a roll-a-way bed at no charge. Each man pays the clerk with a $10.00 bill. Later the manager comes in a tells the clerk he has overcharged the them for the room, it is only $25.00. He gives the clerk 5 $1.00 bills and tells him to return the cash to the gentlemen. The clerk realizes they cannot evenly divide the 5 dollars between them and pockets 2 dollars. He gives each man a dollar and leaves. Now, each man has paid $9.00 for the room; 3 times $9.00 is $27.00, plus the $2.00 in the clerks pocket equal $29.00. Where is the other dollar? By taking the $2.00 out context it appears a dollar is missing, when in reality all the money is accounted for. When the men paid $30.00, there was $30.00 in the office; 30 = 30. When the men paid $27.00, there was $25.00 in the office and $2.00 with the clerk; 27 = 25 +2. To understand the concept of the Zone system you have to have a few standards. If you take a piece of your photographic paper and expose it to room light for 5 second, develop in Dektol for 3 minutes, you will have a maximum black print. If you develop a piece of photographic paper without being exposed, you will have a maximum white print. There are infinite shades of gray between the two, and the gray of the 18% reflectance gray card by definition is middle gray. Adams defined this gray as Zone V print value. In the passages you quote from Book 2, he is discussing the naturalistic rendering of objects in various zones. The reflectance of average weathered wood may not reflect the same amount of light as the 18% reflectance gray card when measured side by side, but a naturalistic rendering of the wood to appear with the same tonal value of the gray card requires placing it on Zone V. I have never said a scene may contain highlights that exceed 100% reflectance. I have said that depending the quality of the light reflecting from the gray card, other objects in the scene can have reflective densities that fall on zones higher than Zone VII. Keep in mind, everything Adams discusses in Book 2 ultimately relates to print values; shades of gray. I don't think Adams would disagree with you when you pose the issue as measuring the gray card in direct sunlight and basing the exposure on that reflectance. The reflectance of the all the other objects in direct sunlight cannot exceed Zone VII. But if you place the gray card in the same scene in shade and base the exposure on that reflectance, you will exceed Zone VII. And when you drill down on the Zone System, his point is make sure when you expose the negative you have enough exposure in the shadows for the texture or detail you want in the print, and adjust the development of the negative to control where the other values fall.

Of course Zone 8 is 3 stops more than the brightness of an 18% gray card when placed on Zone 5, and Zone 9 is 4 stops, and Zone 10 is 5 stops; based upon the definition of "zones" they must be. Walk into a forest and place the gray card on the trunk of a tree and measure the brightness and place it on Zone 5. Then measure the brightness of the surrounding area "in sun" and calculate the zone difference. If you want the tree bark to have a Zone 5 density in the negative, you will probably need to reduce the development of the negative to control the high densities so they will not be "blocked", since they will exceed your 2 1/2 Zone maximum. I admit I have changed the "quality" of the light in this scenario [shade and full sun], but in many photographic situations by placing what you want to be on Zone 5 will have have other objects exceeding 2 1/2 stops. The tonality of the gray in the 18% reflectance gray card represents "middle gray" between the maximum black & maximum white of photographic paper. And as we all know, the card can have applications in trying to determine the exposure of a scene. Adams never said in his basic photo series what you claim in your post where you say "Ansel's maths must have been a bit rocky if he thought that 18% reflectance was 3 stops less than 100%".

I believe Adams said the amount of gray in an 18% reflectance gray card approximates the Zone V print value. If I place an 18% gray card on a white wall in direct sun and there is a 3 to 4 f/stop difference in meter readings between the gray card and the white wall, nobody is going to believe the wall is reflecting 144 to 288% of the light falling on it. And the Zone system is about how much light is striking the negative and controlling the negative densities to keep that texture in the low and high values. We are measuring the brightness of the light reflecting off objects, and "zones" don't double in % reflectance, but in brightness.

Well, I guess Adams was photographer, not a mathematician, and I am not sure how that has any bearing on the original question.

I have never cared for resin coated paper. I ended up using the only box I bought for negative proofs. I suggest you try a box of Ilford multigrade Classic FB. You have the color head that will provide the "variable color" for variable contrast paper. If you selenium tone your prints, this particular Ilford paper tones well at 1:10 dilution. Paul

David, Are you are referring to Erwin Schrodinger, or Ruben Bolling's Schrodinger's cat? Link: Tom the Dancing Bug on Twitter Nerds want to know!

Presently there are two on eBay for about than 1/2 that amount.

In one of Ansel Adams Basic Photo series he has a discussion on the Sinar Six Meter. It was in Book One of the one - five series of books before he published the Revised series that only consisted of Book 1, 2, 3. He had a fairly complete discussion and a few photographs of the meter placed behind the ground glass. Here is a link to the book on eBay, unfortunately it is signed and not priced for just reading. But this is the book with the Sinar discussion. SIGNED Ansel Adams Camera and Lens Basic Photo One Revised Fourth Print HC DJ | eBay

I believe De Vere makes an enlarger that projects a digital file for "silver" printing.

Grolsch beer bottles have a unique cap assembly that some photographers have found to be a good storage bottle.

One of Amsel's assistants, Alan Ross or John Sexton, said it was very liberating to go through the boxes of prints and see run-of-the-mill photographs. I think in the Eloquent Light Adams stated, 12 good negatives [or prints?] a year, is a good crop. Paul

I tone for permanence and a slight hint of purple. The dilutions are to control the immersion time to make sure the toning does not go "too fast", Oriental Seagull responds very quickly at 1+9; 2 minutes and is hard to control the desired effect. And I found Iflord MGIV toned too slowly at 1+9; 12 to 15 minutes. I use a two bath fix; "first" fix is after the "stop" bath and store the prints in a tray of water. At the end of the printing session, I rinse the print and do a "second" fix with the print going into a second holding tray of water. I rinse the prints individually with running water to remove most of the chemicals on the surface of the print and then they go into the selenium toner. From the toner they go into a washing aid, then running water rinse. The final wash is in a archival washer. I hope this helps.