I have done colour negative in my kitchen, using Tetenal kits. It's been a while; I still have one unopened kit stored away.
After years of thinking it was just too hard, I saw someone's results at Flickr, and asked; he said 'just try it; it's not as hard as people say'. Your first film will be a great encouragement.
Temperature control is not very hard, but worth spending some care on. Remember that only the developer stage needs great care over temperature. My water bath is just a washing-up bowl. I have tried putting an aquarium heater in it, just because I had one. Not sure if it's better than just checking the temperature and having a kettle handy, as someone said above.
The kit I use comes with a second set of recommended times, for use at 30 degrees. I use those times firstly because they're longer, which lets me be more precise (my tank takes a while to pour in and out, which is a worry if the developing time is very short), but it makes maintaining the bath temperature easier in winter too.
I have always tried to save my exposed film up until I can exhaust a kit over a couple of evening sessions, rather than having it go bad half-used.
I have tried an E6 kit just once. Despite my care, I got quite a bad rash up my arms. I won't be doing any more of that.
Hi,
I did lots of E6 using Barfen kits. (Not sure if that is the correct spelling, it was over 30 years ago) Colour printing was too much, so just colour transparencies.
I used a heating element in a plastic crate, controlled with a simple on/off switch. This was before the day of RCDs, so I could have electrocuted myself. I also got many burns, touching the heater.
Moving onto modern times, it would be easy to use a microcontroller, Arduino or similar, to monitor water temperature and control a heater, so rather than on/off, the heater output could be varied to heat up the water quickly and then drop back to a lower output to maintain the set temperature, so no 300 degree heater to burn myself on.
I looked into all of this when getting back into film (photography got interrupted by beer woman & curry) but the simple answer was the sous vide (as established, Latin for photography chemical heater) It has temp control, a shielded heater, so no burnt hands, some protection if it gets dry & a pump to circulate the water.
Find a suitable plastic container for the water bath, (which can also be used to store all the developing stuff afterwards). The sous vide does have a narrow min & max water depth, so a little care is needed when adding or removing bottles, I use a milk bottle filled with water to replace a chemical bottle when removed. Obviously, the bigger the water bath container, the less the height will fluctuate, but the sous vide is really designed to go in a cooking pot, so total water volume has to be considered.
Adding insulation to the container will save energy (money) depending on the container, it could be one in side another, to create an air-gap, or stick on polystyrene insulation. I did look at cool-boxes, but did not find anything suitable.
Would be great to see photos of peoples home-made water baths with sous vide or similar.
I really cannot suggest that an aquarium heater is a good idea. Just a second out of water & they go bang & crack the glass.