For both CN-41 and RA-4 color developers, most of the chemical kits require both starters and replenishers. I understand the concept, but why it was made this way? What is the difference between the starters vs replenishers? Can we use starter or replenishers alone if we are short with one of them?
Also, it appears some of the replenishers could be used alone without starter. Any ill effect from it?
a lot of info on c41 here:http://www.apug.org/forums/forum40/6...1-dummies.html
Starter is pretty much the opposite of replenisher! A starter will pre-age the developer - it simulates running some amount of film through the developer, usually by adding bromide and oxidated developing agent. Replenishers replace used and lost active agents as well as the transport loss of the passive agents - i.e. it is developer with a (relatively) increased content of active ingredients, plus (sometimes) extra components to neutralize or bind development by-products.
If you leave out the starter and instantaneously replenish, you'll permanently overdevelop (and lose a bit of reachable density as you sway off the best colour balance) - if you start replenishing after some films or papers, the first few will be less than perfect, but that is all (and there used to be processes where doing a test roll per litre was the official way of starting them). In a nutshell: Replacing starter with replenisher is worse than using none at all.
For a fresh new tank, do I mix starter with replenisher according to the instruction? or I just use starter alone and then add replenisher later on?
YMMV. What process and what size/packaging are you talking about? Some small process kit sizes do away with regular stock entirely, and make replenisher their main developer product, starting up either with a ready-mix "starter" (really a pre-started stock) from a separate set of bags/bottles, or a starter additive that reconfigures replenisher into started stock. If your instructions tell you to add starter to replenisher for a fresh tank filling, you have one of the latter.Originally Posted by RedSun
In the main C-41 and RA-4 processes as defined in the eighties, and as used in large lab scale, you'll usually have stock, a starter additive and replenisher as separate products/recipes, the latter sometimes formulated as modifiers that convert stock to starter respectively replenisher, as both are derived from stock.
See below.
From what I read, you mix replenisher with water to make working replenisher. Then you mix working replenisher, starter and water to make starting developer to fill the new tank.
Going by the inscription on the box, you are right. As I said, this is one of the two common "simplified" developer kit systems.
Replenisher is like slightly-concentrated developer. When you use the developer, it wears out a little and you need to add some replenisher to bring the activity back up to normal levels.
When you're starting out, pure replenisher is more powerful than a consistent aged developer. So you add starter to it, which has the same effect as running a few films, i.e. it wears out the developer a little.
You cannot develop film in starter alone, starter is like anti-developer. You can often use replenisher as developer without any starter, but there may be implications for your process time etc.
You really need to read the Kodak Z-series documentation for whichever process you're considering. The FAQ in my signature may also help.
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Analogue Photo and Film FAQ (for APUG)
Open Source F/Stop Timer
The starter/replenisher also applies to bleach, fixer, stabilizer? I've seen some chemicals say bleach replenisher, etc....
In large labs, everything is replenished - but the less critical baths (i.e. anything other than developers) tend to make no difference between stock and replenisher, and hence know no starter either.
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