How a Computer Programmer and Special Effects Guru Gave Birth to Photoshop

February 19, 2015

By Greg Scoblete

Photoshop turns 25 today. To celebrate, Adobe has published a Q&A with its co-creator, Thomas Knoll, that provides some interesting insight into how the program was born.

Just before he set his hand to developing Photoshop, Knoll was a graduate student tackling a challenge that still consumes computer scientists today: teaching computers to recognize and understand images. His brother John, meanwhile, was employed at Industrial Light and Magic doing analog image composition. ILM had just begun to experiment with digital processing using a scanner to scan in frames from a movie, process them, and then write the images out to film.

“My brother saw that and had a revelation,” Knoll says. “He said, ‘If we convert the movie footage into numbers, and we can convert the numbers back into movie footage, then once it’s in the numerical form we could do anything to it.’ We’d have complete power. With digital, you can change every pixel into anything you want, and you can perform any operation with the film footage that you can imagine. Then he said, ‘This is the future of special effects in movies,’ and decided to teach himself computer graphics in his spare time.”

Knoll goes on to explain how, working with his brother, he developed the “levels” dialogue in Photoshop: 
“…[John] pointed out that some of the computers he used had different gammas in their display, so the new combined software application had to also be able to adjust the gamma of an image—and that reminded me of my darkroom days, where I used chemistry, different kinds of paper, and various adjustment knobs on the equipment to change images’ brightness, contrast, and so on. Through thinking about how all of those tools worked, I came up with the ‘levels’ dialogue, inventing that as the first major adjustment feature of our new software application, which soon came to be called Photoshop.”
According to Knoll, back when Photoshop was created, the only way to produce photographic-quality output from the program was to create four-color separations on film and take them to a printing press where it would cost a cool $2,000 for your first print or about $35-to-$40,000 for an entire roll of 35mm film. 
You can read the entire Q&A here