Do we really need the frog tongue?
We know that Polaroid film is much more sensitive than other instant film. In particular, the first few seconds after the photo ejects from the camera are crucial. Polaroid therefore developed a solution, especially for the older box cameras (600 series) and folding cameras (SX-70). During the time of the Impossible Project, this solution was called a "Frog Tongue," but Polaroid now simply refers to it as a "film shield." On newer cameras, such as the I-2 used in this test, the film shield is built in as standard.
In the experiment below, I took three photos of an architectural building in Maastricht on a sunny day: the Bonnefanten Museum Maastricht.
Photo 1: After the photo ejected from the camera, I did not protect it from ambient light. In other words, I did not use the film shield.
Photo 2: Here, I kept the photo under the shield for 10 seconds and then allowed it to continue developing in ambient light.
Photo 3: Here, I kept the photo under the shield for 10 seconds and then allowed it to continue developing in the dark (inside a box) for at least 20 minutes.
Overall, the differences are not very large, to my surprise! However, you can clearly see that the contrast increases as more care is taken to protect the photo after it ejects from the camera.
Conclusion: It is advisable to protect the photo from ambient light for at least the first 10–15 seconds. Ideally, you should be patient and allow the photo to develop calmly in the dark.