Cooked Film vs Standard Fresh Film

So whenever you buy film locally, 9 times out of 10, especially if its a small shop, they’ll tell you “make sure not to leave it in your hot car”. Ive been told this dozens of time so I wanted to put it to the test. So The two stocks used were Portra 400 and Illford XP2. So I left one roll each in my car for 10 days, with the average temperature being 60-80 outside and the car being in constant sunlight. Out of the two photos, the one on the left is the new fresh roll and the on the right is the one left in the car and was “cooked”

So there really wasn’t a big difference, especially not one worth worrying about. The cooked Portra is a little bit darker, duller, and colder overall. It no more grainy than the standard Portra. The cooked photo really looks like the standard if you threw it into lightroom and lowered the vibrance and exposure, and if you made the white balance cooler. The cooked XP2 is a even smaller difference. It is a tiny little bit darker, and is the tiniest bit more contrasty, adding something like a red filter or even darkening the image by half a stop in lightroom would make the photos seem more different.

So long story short. If you accidentally leave a roll of black and white film in your car you wont even really notice a difference or have to worry about it. If you do the same with color film, you may notice a small bit of color shift and the tiniest bit less sensitive to light. So if you do leave your color film in a car, possibly overexpose by 1/2 to a full stop and you’ll be more than set, or just boost your colors and exposure a bit in lightroom and you’ll be fine.