What happens if I am developing my negs and don't use a stop bath, all i have it developer and fixer,
Use water instead of stop bath. A lot of people do this. But the fixer life will be shortened by this, if im not mistaking.
You can use water but it takes longer to stop the action of the developer than a stop bath. Also, neutralising the alkalinity of the developer with an acididc stop bath tend to preserve the strength of the fixer. You could make your own stop bath by diluting acetic acid (I am not sure how much; Google is your friend) in water.
What happens, is that development is not stopped completely with the use of a water rinse before fixing. There is nothing really "wrong" with this method, but you may need to adjust your development times because of this. An advantage for using a water stop is that development will continue most in the shadows, giving you a method of control for shadow detail. Can be done with paper as well, but not all respond well to this method. The recommended procedure with a water "stop" is drain the tank, refill with water, agitate for 10 seconds, pour out, and repeat for one minute or five cycles. Sheet film, wash in a running water tray for a full minute, drain the sheet then fix. Glacial Acetic Acid is dangerous to work with, so don't get it on you or breath the fumes and pour the acid into the water not the other way around. For films start with 28% Glacial Acetic Acid, mix 100cc for each 1/2 gallon use for 30 Seconds. There are other buffered formulas that are better, with less risk of pinholes. White vinegar can be used 1:4, but I would not use it for paper as you run the risk of discoloring the print as vinegar is not as pure as glacial.
I recommend NOT using stop bath for negs (only for paper) because it can damage your negs and actually create little pinholes in the emulsion. This may not happen every time, but when it does happen you'll be bummed. Use a 30 second water bath, instead, with continuous agitation.
I use water and have heard the same as above. On Photo.net there is a discussion of not using a stop or water and going straight to fixer. Never tried that but many claim it's your best bet. Haven't had a "test" roll to try it.
If you go straight from commonly used developers to commonly used fixer the fixer will stop the development, but your fixer will exhaust much sooner. Fixer tends to be the most expensive chem, so most folks want to prolong it's life. Also while you can see if your fixer is exhausted when fixing film, and just refix with fresh fixer, when making prints you may not be able to tell if your fixer is exhausted for days, weeks, or even years when the photo starts getting darker from being exposed to light. I never had a problem with stop bath pinholes with 35mm film, because it's so grainy they are usually hidden, even in fine grained films, but they become much more noticeable in medium format and 4x5. I stopped using acid stop bath, and went to water bath because of pinholes in 4x5. eventually I began using some less common developers (such as Diafine) and fixers (such as TF-4), and they don't like acid at all so a water stop bath is recommended instead of an acid stop.
Going straight into fixer also increases the chances of staining in the emulsion, a much worse problem then a pinhole. Pinholes occur when left over sodium carbonate from the developer hits the acid in the silver rich dense areas of a negative creating carbon dioxide gas. This can easily be solved by buffering your stop bath, diluting your stop, or using a weaker acid like citric or sodium bisulfite solution. Using a water rinse is fine, as long as you have compensated in your exposure and developing techniques. But, if you want to halt development immediately, using an actual stop bath is the only way.
