ian_beales

<p>Thank you all for your help and comments. It turns out the problem is with my monitor calibration – there is no posterization when viewing the picture on other monitors. It looks like my colour management needs a bit of work!</p>

<p>I occasionally print my own pictures on an inkjet printer and use a printer profile that results in the prints matching the monitor. I thought the monitor profile was OK too but apparently it is a bit wonky. Fyi when I view the picture on my monitor the red channel in the areas of concern (side of face and side of shirt) is at 255 so something is clipping – that something has to do with the monitor, not the camera.</p>

<p>Ian</p>

<p>Mark,</p>

<p>There are 2 areas of concern: the distinct line between the side and front (bottom) of the shirt; and the line between the cheek and front of the face. It almost looks like her face is dirty.</p>

<p>I know the back of the shirt is blown out and that there is a distinct line between the back and the side but am not concerned about that portion.</p>

<p>Ian</p>

<p>I’ve had the occasional shot with my D70S display posterizing since new. Attached is a recent example exactly as it came out of the camera. There is a distinct line between the subject’s cheek and face, and between her side and front.</p>

<p>In order to track down what causes this I’ve started setting most of the custom camera settings manually. This shot was taken with the dial set to P-mode, Color Mode Ia, Sharpening, Tone and Hue manually set to 0, WB set to Cloudy with -2 Mired adjustment. About the only thing I did differently from most of my shots is have the Saturation adjusted to + (I normally keep it at 0). I was taking landscape shots and had the Saturation turned up.</p>

<p>Any ideas how to prevent posterization?</p>

<p>Ian</p><div></div>

Aaron, the 0.3 density change per stop is logarithmic - log 2 is 0.3. Neutral grad filters they are typically in 0.1 density increments so if you want a 2-stop grad filter it is 0.6 density. 10^0.6 = 4 (2 stops).

 

I check negative density using an incident light meter which has 0.1 stop resolution. I place the meter on the enlarger table and project the negatives onto the meter dome. I know that the meter is fairly accurate and it seems to be repeatable.

 

Years ago I got into the habit of exposing frames 36 and 37 of most rolls at Zone I and VIII as a test. Since I load my camera in a way that gives unexposed film at the start of the roll I've got my Zone 0 for reference density, and since my negative sleeves hold 7 rows of 5 negatives I use only 35 frames per roll. So what to do with the other 2 possible frames? It seems like a useful way to justify a quirky habit.

The range in density of a negative is quite different from the range of relative light intensity of the subject being photographed.

 

If you're developing for a condenser enlarger, the Zone V density would be about 0.6 above film base plus fog. The corresponding densities for Zones I and VIII are about 0.1 and 1.2 above film base plus fog respectively. Density varies by about 0.3 per stop so there are about 2 stops (0.6 density) difference between Zones V and VIII and about 1 2/3 stops (0.5 density) difference between Zones I and V.

 

I've done what you're describing with good sucess when doing film speed and development testing - you just need the zone/density numbers to work toward. I usually use just 2 points for testing: Zone 1 and VIII. As long as the densities are what I want for those Zone exposures then I know my film speed and development are OK.

 

Film manufacturers publish curves showing density vs relative exposure which should give you a starting point for densities. The website http://www.cicada.com/pub/photo/zs/ has some interesting info on film density vs exposure.

A negative held against a flat black (really, really black) background looks something like a positive. This is how some early photographs were displayed. It won't look as good as a contact print.

Neil, we may have to agree to disagree on this issue. I wish I could find the reference to the manufacturer's definition of exposure latitude being the "straight" portion of the response curve. It was also in a quiz on a photo magazine website a while back - intended to clear up misconceptions about what exposure latitude really means.

 

If I come up with a reference I'll try to contact you offline.

Neil, "exposure latitude is the number of stops where the curve is straight" is actually the definition used by film makers (I've probably dumbed down the actual definition since there must be some allowable deviation from a straight line). For many years I thought exposure latitude referred to the total range of exposures that could be captured and differentiated on film. The definition made more sense to me when I realized the limitations of range of negative density that can be printed on paper.

I meant to answer your other question regarding 1.0 density relative to mid-grey.

 

If you use a condenser enlarger your film density (i.e. actual film density - film base - fog) would typically range from about 0.1 to about 1.2. Mid-grey (18%) is Zone 5, which is in the middle, so the density would be midway between the upper and lower usable density range, or about 0.65. Different films have different curves, and changing developers gives different curves for the same film, that is one of the reasons why the look of the printed picture is different with different film/developer.

 

Film testing to establish film speed is a piece of cake. Fine tuning the dilution to give the film density you want at the exposure you chose is more bother than I care to endure, but can be done.

Exposure latitiude is the number of stops where the curve is "straight".

 

For example, if the curve is straight from log 1 to log 4 exposure that is a difference of 3. 10^3 = 1,000 which is about 10 stops (10 stops is 2^10 = 1,024). The actual math is (log 1,000)/(log 2) = 9.97 stops. Keep in mind that the Ilford curve uses relative log exposure so they are not commiting to any give exposure value for any given density - it is all relative.

 

Present-day colour negative films typically have a tremendously long straight section in the response curve which is why it has so much latitude.

I'm very much an analog person. I created a sheet of semi-log graph paper with log time on the X-axis and temperature on the Y-axis. I manually plot the time-temperature data from the film I use (mainly Tri-X) which results in a straight line in the same manner as shown on the Ilford graphs that are available on the web.

 

In reality, I move the straight line to the left (maintaining the same slope) to suit actual conditions based on film testing. From that point onward it is a simple matter of measuring the temperature of my chemicals and looking up the appropriate development time.

 

I'll try to attach the graph which is a WordPerfect document. It does not reproduce well with Word :(

I shoot Tri-X (35mm) at 200 and develop in Xtol 1+1 for 6:50 at 20C for use in a condenser enlarger. The time recommended by Kodak is 9:00 at 20C for 400 speed using a diffuser enlarger. My time was determined by determining personal EI, etc.

It appears that you've got the new stuff based on the colour scheme, although I cannot confirm it. You'll be quite safe to assume you've got the new stuff when doing your developing tests since the developing times for new and old are quite close. The final proof is in the negative edge numbering. The new stuff is marked 400TX, the old is marked 5063 TX.

The "new" versions of Kodak's B&W pre-rolled 35 mm film is packaged with the word "Kodak" printed in red. The previous versions had "Kodak" printed a different colour (I think it was either black or yellow).

 

The bulk film is likely labeled in a similar manner.

I agree with Mark regarding further testing of speed, development combinations.

 

I typically use Tri-X but needed to shoot something at EI 1600 last weekend so used P3200 (New) for the first time. I tried developing 2 test rolls before developing the "good" roll to in order to get close to the right time using Xtol 1+1 and was surprised at the results. Since I use a condenser enlarger I developed for the time recommended in Kodak's data sheet f4016 for EI 800 (as recommended in the data sheet). Through a moment of brain fade I ended up developing for only 85% of the recommended time and the negatives were grossly overdeveloped. The second test roll was developed for 77% of recommended time and was still overdeveloped. The "good" roll was developed for 69% of recommended time and were printable but were still a bit high in contrast.

 

The moral of the story is to test for film speed using your methods before shooting something that is critical.

I've been doing something similar when testing for film speed and contrast. I shoot a blank subject, like a piece of paper, at the range of exposures to cover at least Zones 0-11, process the film, then project it through my enlarger onto my incident light meter (also a Sekonic L508). There is adequate light to get all the readings necessary without the use of a booster, and that is when using a 75W light in a condenser enlarger. I move the enlarger head all the way to the bottom of its travel so the projected image is only slightly larger than the light meter integration dome.

 

This method is much faster than printing test strips to check contrast.

My testing of Tri-X in Xtol 1+1 shows a speed of 200. I haven't used other dilutions for Tri-X. I develop for about 7 minutes at 20C which gives me the full range of print densities on variable contrast paper with a #2 filter when using a condenser enlarger.

An example of Brian Henson's IR work can be found at

http://www.westlandsart.com/photography.html

I have not used Kodak HIE yet but was recently at a brief seminar on printing techniques in Calgary when the discussion drifted to how Brian Henson, the presenter, had exposed his infrared work.

 

Brian used a number 25 filter and exposed at 1/125 sec at f11 for direct sunlight, opened 1 stop when hazy but bright enough to see a distinct shadow of his foot when he lifted his foot off the ground, and opened 2 stops when he could not see a distinct shadow of his foot.

 

A couple of other tips he offered were to "always" load and unload the camera in complete darkness, not to worry about keeping the film cold, and include a lot of foliage in the picture as reference otherwise the effect of infrared is lost. I believe he developed the film according to the Kodak recommendations for the contrast that he wanted.

 

His infrared work that he displayed? Pretty amazing.

 

Brian, my apologies if I have misstated anything you said.

To expand upon Pete's answer, all film produced since the early 1950's has been safety film. The early film was based on cellulose nitrate (often referred to as nitrocellulose) which is easily ignited by static discharge or even by mechanical shock. Safety film was so designated to indicate it did not have the same ignition hazards asssociated with it.

 

Hollywood had a hard time with cellulose nitrate film due to degradation of the film and resulting increased fire and explosion risk. There is actually a National Fire Protection Associate standard addressing the specific needs of fire protection for storage of motion picture film. This standard came about partly due to the loss of several film storage warehouses due to film fires. It probably isn't much of a big deal now since most cellulose nitrate films have been reprinted onto modern film which eliminates this fire risk.

 

Cellulose nitrate is still in common use in some industries, such as the production of printing ink. Special precautions are used in handling it such as keeping it wetted with solvent until immediately before use. Although the solvent is a risk in itself, it is far less of a risk than of the potential explosions from dry, finely divided cellulose nitrate.

I've used several rolls of 35 mm recently. I shoot primarily Tri-X and I'm looking for an additional slower speed film.

 

I expose it at EI 50 and develop in Xtol 1+1.5. It looks like 8 minutes at 20C is about right for printing on my condenser enlarger. When exposed correctly based on the above, it is extremely difficult to find any grain in an 8x10 print. The amount of grain is likely similar to what you'd find with TMX or Delta 100. When overexposed the results are quite awful as they are with most B+W.

 

I haven't seen anything that indicates Acros is a tabular grain film but it has some of the same developing characteristics such as a very flat time/temperature development curve (which makes it sensitive to developing time or temperature), and it has a pronounced pink stain which takes a fair amount of rinsing to eliminate.

 

As far as the look is concerned, beauty is in the eye of the beholder. I'm used to the Tri-X look so Acros looks smoother. It appears to have more subtle texture changes which may be partly due to the finer grain with the resulting additional information captured by the film. Your developing and printing techniques will probably give slightly different results from mine.

Lex,

 

I've been a happy exclusive Xtol user for about 3 years now and think it would be a shame if you gave up on Xtol before giving it a fair chance. It may give your negatives properties that you have been looking for.

 

From your previous posts it appears your processes are done consistently well but you goofed when you gambled by using a package that was obviously "off". I check every package of Xtol before I buy it by rocking the package back and forth to see that the material is free-flowing. If it isn't, I don't buy it. I also check the same way before mixing it but haven't had to throw out a package that I have been storing for a while.

 

I hope you give Xtol another chance with a package that you know has no obvious flaws. As an analogy, if you always used ABC tires with success but decided to try XYZ tires and ended up with a blowout after noticing a nail sticking out of the sidewall of the tire, are you going to give up on XYZ tires?

Lex,

 

Thanks for your answer.

 

I am relatively new to "serious" B&W and am restarting my darkroom after a 1 year absence. I hope to experiment with different film/developer combinations, but in a logical fashion so that I can learn from it. Part of my restarting exercise is to decide whether to continue using my condenser enlarger or switch to a difusion. Although the appeal of dust being less of an issue with a difusion enlarger is attractive, I am also expecting that with increased development times for a difusion enlarger I will be on different set of characteristic curves which may give me results that I may find more to my liking.

 

Normally it wouldn't be a hard decision to switch to a difusion enlarger. Right now I am in a temporaty state of negative cash flow so I either have to put up with a bit of short-term financial pain or continue my quest with my condenser enlarger.

Lex,

 

I am curious as to the reasons you changed from a condenser enlarger to a difusion enlarger.