Unfortunately we do not carry 4.5" round filters. You may want to check with Yankee directly; Distributed By - Regal PhotoTel: 800-317-5824 or 414-645-2050 Website http://www.arcat.com/

The type of lamp that normally fits inside of this safelight is 15 watts/130V with an E26/E27 base.

We are not sure what you are asking so we will answer both ways. 1. No, you can develop films using a safe light. You use liquid chemicals. 2. Generally, no, you should not have a safe light on in your darkroom while sheet film is being developed in the trays. Here is what Kodak says regarding a safe light while developing a typical sheet film, Kodak Tri-X: "Using a safelight will affect your results. If absolutely necessary, after development is half complete, you can use a safelight equipped with a KODAK 3 Safelight Filter (dark green) with a 15-watt bulb for a few seconds. Keep the safelight at least 4 feet (1.2 metres) from the film. Run tests to determine that safelight use gives acceptable results for your application. For information on safelight testing, see KODAK Publication No. K-4, How Safe Is Your Safelight?"

It is approximately 8 x 6" in size.

No wont work for color prints. You will need complete darkness for color prints as the paper is sensitive well into the red part of the spectrum

I used to use Illford products almost exclusively when I was doing wet bench processing. I believe the information that you are looking for might be found on the mfg.'s website. The answer is no, . . I changed the gel in my lamp to a lighter yellow which I use for work with photo-resists used in glass etching. My resist is exposed with UV. I hope this helps you!