Photograph Negatives Explained

The concept of photo negatives can be confusing. You see them in film developing centers, cameras, and photo envelopes, but you may not understand them. So what exactly are photographic negatives and why are they used? Hopefully this article will shed some light on the subject, so to speak.

A photo negative image is an exact copy of a normal image, but the colors and tones are reversed. I'm sure you've seen the reddish film strips that come with developed photos in envelopes. Those are negatives. If you want more copies of your photos you take them from the negatives. Look at them and you'll notice that the bright and dark tones are reversed and the colors are opposite as well. What should be blue is yellow, what should be purple is green, and so on (based on the Red Green Blue color model).

Negative images are created by the film's chemical reaction to light. The unexposed chemicals wash away and the negatives become opaque, or seen through. To make a copy of a photograph from a negative, another negative is made off of that, actually creating a positive. This might remind you of algebra, where two negative numbers multiplied by each other become a positive. This is considered the two step process in photography. There are other processes such as positive, or slide, but the negative is the most common chemical based process.

The most common color negative film is called C-41. The negative is made up of different colored emulsions layered onto an acetate or polyester base. Each layer is sensitive to certain colors and underneath each layer are collodial silver or dye filters. When exposed each filter removes light and exposes the layer beneath it. When developed, the dye couplers inside of each emulsion layer produce the colors.

So why still use photo negatives when we now have scanners? Convenience and quality. Typically when you scan an image you'll lose detail, whereas with the negatives, you have entire original albums intact in a small envelope. If you have photograph negatives lying around that you'd like prints of, your best bet is taking them to a photo lab. You can scan negatives yourself though if you own a properly equipped digital camera or photo scanner. Most regular flatbed scanners won't do this, but with a fluorescent lamp and a high resolution scan you can manage it. Of course with the popularity of digital cameras photograph negatives are needed less and less. But it's still good to understand the basics of photo negatives.