 Ron |
Color Film Negatives Hello everyone, When I take my photos in to be developed, there are various colors in the negatives - such as a purple flower may appear red in the negative. Why? I am using film of various speeds. It doesn't say slide film on the box so it must be color negative. The camera is a Minolta Maxxum 9xi. I am just curious.
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Mark Feldstein |
Actually, Ron, a very good and reasonable question that I should probably defer to our resident expert on photographic processes, Alan Marcus. In the meantime, however, when processed, the dyes in color negatives correspond to other dyes in color photo paper. As you've discovered, what you see is not what you get. Red produces green, green produces red, yellow may produce blue, purple comes out red. BTW, color negatives produce slightly better color saturation when they're overexposed a bit, say by 1 stop, unlike slide film that does better slightly underexposed by say 1/3 or 1/2 a stop. There are lots of combinations unlike the more straight color reversal process of transparency film printed on reversal paper. In the case of transparencies, the positive image you see on the film is printed on reversal paper to produce a positive image.
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Alan N. Marcus |
Hi Ron - thanks Mark: Early photographers took pictures using metal plates coated with light sensitive chemicals. When developed these picture looked ‘OK’. The problem was, each photograph was unique as their was no practical way to make a duplicate copy. The answer was to use film in the camera that yielded a negative image. This is true because the finished negative could be held in contact with paper coated with light sensitive chemicals (photo paper). This sandwich was exposed to light in a controlled manner and then developed. The results yield a high quality positive prints on paper. Negatives allowed photographers to make countless copies. Additionally, the printing exposure constituted a re-taking of the original. Now photographers can control this second exposure in such a way as to compensate for errors made taking the original. Latter we learned to project the image of the negative onto photo paper. This allowed either a blow-up or a reduction as to final print size. The negative is an exact opposite of actuality. All shades are rendered their counterpart or opposite. What is black on the subject is clear film on the negative. What is white on the subject is black (opaque) on the negative. Middle gray is the same on both. Photo engineers learned in 1861 from Clerk Maxwell, that we could make a full color picture using just three colors. His was the first. Further we learned that human eye has three color receptors and that we see the world via red, green and blue stimulus. Color film mimics our anatomy. Films are made with three light sensitive layers, following our model. We call these colors the light primaries. Just like back is opposite white, all colors also have an opposite. When we study light and color we discover the spectrum in the rainbow and when we pass white light through a prism. The spectrum is a band of colors red at one end and violet at the other. If we bend this spectrum into a circle we get a color wheel. Now on this wheel we can draw three equal distant spokes, if we do, one spoke starts at red, passes through the center and if continued, struck the other side of the wheel at a color that looks blue-green. This color we call cyan and it’s the opposite or the negative of red. Scientist like the word complementary so they say red’s complement is cyan. Doing the same for green we discover that the complement of green is a red-blue we call it magenta. For blue the complement is yellow. So we have the three light primaries and the three complements. When we make filters and shine a light through them: Now the subtractive primaries are exactly what are needed when it comes to making a color negative. After developing: Thus a red flower appears cyan on the negative. Because color negatives are a means to an end, they are not viewed by the public. We can put lots of magic into to them. One such magic is a two layer colored mask made using undeveloped dye. Its purpose is contrast control and to bolster the imperfect cyan and magenta dye that must be used at the current state of this technology. This masks make the negative appear orange. It is actually two positive images superimposed on top of the three negative images giving the color negative a total of five images. Some specialized color negatives are even more complex. Alan Marcus (marginal technical gobbledygook)
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Brenda D. |
Alan, I would I like to ask a guestion,if you print a photo that somehow the film got exposed to the light and puts the big red and yellow streaks in the print is there any way to salvage them? The only thing I have found so far the make the prints semi exceptable is to do them in B&W if they are not too far gone. thanks Brenda
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Alan N. Marcus |
Hi Brenda, Sorry to hear your film somehow got fogged. I suggest you take the negatives to a one-hour shop and have a set of prints made. You want to patronize a modern shop with a printer that sports a digital print engine. Ask them about their printer. The older types are optical, they uses a lens to project an image of the negative onto the print paper. The newer models feature a scanner which digitizes the negative and prints on photo paper via a laser or virtual negative or light valve - print engine. You can ask for both black & white and color prints. I suggest 4x6 inch size. With this printing service, ask to have the digital files burned onto a CD. You need to know that many shops scan at a low resolution. The key work here is ‘base’ an industry coined word that describes resolution. Base is 512x768 – 4Base is 1024x1536 – 16Base is 2048x3096. This term comes from early production engineering between Kodak and Phillips as the Photo CD was hatching. Nevertheless BASE in the common language of the minilab. Not every clerk/operator are created equal however Ask for a 16 Base scan and a Photo CD – you may need to settle for 4 Base. In any event you will have a digitized image. Now you can take the CD home and work with your photo editing software and attempt to improve the image. You can do this! Ever consider a career as one of TV’s crime fighters. This is routine on NCIS Abby does this all the time. Best of luck, Alan Marcus (marginal technical nonsense)
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Brenda D. |
Alan thanks for the advice, I use digital, this was a friends photo and he ask if I could do anything to help with the photo since it was one of his uncle that had passed away, I got all of the photo corrected but the 2 Very red faces and I hit a brick wall with them I just do not have the know how and probably not the best software for the job. but he loved the B&W and was pleased to get any results at all, and yes I do some photo work for the local pokeys on occasion.nothing too interesting though.
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