Why does developer temp matter?

<p>Hello all,</p>

<p>I recently learned how to process Kodak Tri-X 400 B&W film. I know that the developer needs to be at a very specific temperature and that you can compensate for other temperatures by changing the amount of time that you use the developer. What will happen if you overdevelop or under develop film? Can this effect be used as a technique to alter the way the negatives look or will it just ruin them? Thanks for any help you may be able to offer!<br>

Nick</p>

<p>the temp changes the developers activity... higher temp more active, more contrast. Lower temp, lower contrast. Altering time based on temp compensates for the temp based activity change.<br>

Overdeveloped film can have highlights (the dark areas on neg) with no detail. Under-developed, the tones may not have enough separation. If you over develop too the point that your highlights have no detail, there's nothing you can do to recover when printing. Different grade paper (or using VC paper and filters) allows you to 'rescue' the situation somewhat but the range is limited (grades 0-5, less if using a colour head). <br>

Remember that shadow detail is controlled by exposure... highlights controlled by development...<br>

So, Expose enough, and develop just enough...</p>

<p> </p>

<p>68 degrees F or 20 degrees C are the most often recommended temperatures, although that varies somewhat with the developer/film combination. Check out the Massive Development Chart to get a better feel for the effect of temperature on developing time. One reason to avoid high temperatures is in some cases it make the developing time uncomfortably short.</p>

<p>It is simple physics....temperature increase causes the chemical reaction (development) to speed up and temperature decrease causes the reaction to slow down, each with specific consequences. Additionally, remember that the silver crystals are generally embedded in a gelatin layer on the film base. Too high a temperature, or too significant a temperature change during the complete development process (development,stop bath, fixer, washing) may cause reticulation due to different rates of expansion/contraction of the layers. Nige's comments above are right on the button, especially for somebody who is relatively new to the process.</p>

<p>Thank you all for your responses. Has anyone ever seen someone purposely heating or cooling to developer in order to increase or decrease the highlights for a unique look to your pictures? </p>

<p>Using developers at very low temperatures is used by some folks for developing very old (20 to 50 years) film to minimize base fog. It may even be done with a very high-contrast developer. But this isn't something that's normally done with fresh film freshly exposed.<br>

What you want most in developing film is the ability to do it <strong>repeatably</strong>. You want an repeatable thermometer. You want the temperature to be stable for the duration of processing. You want consistent agitation. You want the developer to be of consistent activity. Processing with developer at room temperature makes this all easier.<br>

There's lots of control over development at 68F, by controlling time, or (with some developers) using stand techniques. You'll get more difference in the HD curve by using different developers than you would by using a given developer at extreme temperatures. Get a copy of The Film Developing Cookbook.</p>

 

<blockquote>

<p>Has anyone ever seen someone purposely heating or cooling to developer in order to increase or decrease the highlights for a unique look to your pictures?</p>

</blockquote>

<p>You can print a negative any number of different ways, but you can only develop it once. It's best to develop so as to get the most amount of information on the negative so that you have more leeway in the printing. If you blow highlights in developing, there's nothing you can do to get them back. If you screw something up in printing, all you've lost is a sheet of paper and a bit of chemicals.</p>

<p>Within the normal range of 68-75F, developer temperature has no noticeable impact on contrast or the look of the image as long as you adjust the time accordingly to get proper development. There are all sorts of fancy tricks out there, but developing at extra-low or extra-high temperatures are not part of everyday darkroom practice and not something I would recommend quite yet if you are just learning to develop the film. Better to learn the basics first. If you don't, you won't understand what's happening when you experiment and won't be able to get consistent results.<br /><br />If you want more contrast or less, you are better off doing that on the printing side through the use of variable contrast paper and the appropriate filters. Cory is correct -- you only get to develop the film once but you can make as many prints as you like.</p>

<p>This is totally my speculation, but after using many types of developers and film, I've come to realize that photography is not an exact science, so certain standards were formulated as a starting point, like ASA or ISO. Through discovery, it was realized that chemicals mix or disslove better at certain temperatures, and certain chemicals perform better at certain temps, like hydroquinone, which doesn't become active at low temps.</p>

<p>When shooting with film, you are basically recording the shadow area of the scene. If you overexpose, you are bringing more of that area to light. The <strong>chemicals</strong> and the <strong>agitation</strong> used to develop the film brings out the highlights. The key is produce a negative that is balanced. Printable highlights, wide range of mid-tones, and detail in the shadow areas. These things vary based on how an individual sees the scene in their minds. A GPS has to have a starting point to take you to your destination. 68 degrees is that point in B/W film development.</p>

<p>http://www.amazon.com/Black-White-Photography-Manual-Revised/dp/0316373052/ref=sr_1_3?s=books&ie=UTF8&qid=1426023880&sr=1-3&keywords=henry+horenstein</p>

<p>Henry Horensteins book will help with your questions.<br>

If you can't tell an underdeveloped or overdeveloped negative from an underexposed or overexposed one you will have problems for decade to come.<br>

It is all about the basics and he lays it out in a clearly written book.</p>

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<p>Has anyone ever seen someone purposely heating or cooling to developer in order to increase or decrease the highlights for a unique look to your pictures?</p>

</blockquote>

<p>There is an old trick in printing, of rubbing a spot with your fingers, which warms up the developer on that spot and develops it faster. Not so easy to do for film.</p>

Im curious to know how The temperature can be manipulated to gain a desired effect on the photos