As I already said in former posts, see as reference this post, it is possible to develop C-41 films at room temperature. The last film I developed gave more acceptable results. I am talking from Dignan's 2-bath developer that I have been using for quite a long time, but I am not completely satisfied with the color rendering of that method, still the idea of developing C-41 at room temperature beeing a great target.
Some time ago, when trying to apply Dignan's method with a warm 2.nd bath, I measured the pH before and after heating and I found out that the heated bath has a higher pH. So, I am trying to achieve better results using room temperature at higher pH for the second developer bath, adding some Sodium Hydroxide to the it.
After preparing a 5% solution of Sodium Carbonate (50g per Liter) with 1g per Liter of Potassium Bromide, I added, with a dropper, the equivalent to 1g/L of Sodium Hydroxide.
I used semi-stand developing technik for the 2.nd bath, that is to say, 1 minute constant agitation and then some turns per minute. I choosed this technik because I already tried stand and constant agitation. I gave following times: 10 minutes for the first bath and 10 minutes for the second, better more than too short, remember that overdevelopment will not happen because the amount of developing agent (CD4) is limited.
Another improvement I may report is what grain is concerned: less grain, I think the semi-stand development is aproved by now. And no surge marks, which occur in stand development.