With all the chatter about the overuse of Photoshop in the fashion and glamor industry, it makes you wonder - have women been being tricked into chasing after the beauty standards of Hollywood for an entire century, beauty standards that don't even exist? In the 1930's, you can imagine how little the public knew about the retouching of the photographs they saw. At least today, we have the internet to show us the before and after versions. So how did they do it before computers and digital programs to remove wrinkles and bad shadows? It was all done manually, in the darkroom, on the actual film or while transferring the image from the negative. It was common for photo artists to add in the touches with fine brushes and special inks and paints.
Most of the facial smoothing in the Joan Crawford picture was achieved through dodging and burning - the process of allowing more or less light to certain areas of the image while the negative is being projected to the photo paper. This allows some of the hard facial lines and shadows to be lightened up. It's a very time consuming and difficult task, taking hours in the darkroom to perfect one photograph. You will notice in present day Photoshop, there is dodge and burn tool named after this antiquated, manual technique.