I have used TMX with D-76, XTOL, HC110, and PYRO. I ran my initial film test us ing PYRO (really dangerous chemical with must be handled with extreme care). I did not know at that time that the yellowish green stain would cause me a small problem when using a Dichro enlarging light source. What problem you might ask. Variable contrast paper has two layers (hard and soft). The yellowish green t one of a PYRO negative acts like a low contrast #0 or #1 filter. This must be o vercome by dialing in additional magenta to achieve a particular contrast (examp le: a non-pyro negative might only require a magenta setting of 30. That same n egative developed in pyro could possibly require 60 units of magenta to achieve the same print contrast). Needless to speak of the Health concerns related with pyro.

The D-76 and XTOL for me did not give the latitude I needed with respect to dilu tions (for N plus and N minus development) while trying to maintain a constant d evelopment time.

I have since settled on HC110 and TMX and TMY. HC110 is sold in concentrated fo rm which must be diluted to make a stock solution. I make all of my dilutions f rom stock solution. It has a wide dilution latitude. My objective was to find a particular development time and keep that particular time throughout the N-4 t o N+4 Zone Scale System. HC110 will allow you to do just that. I have used it as strong as 1:2 for N plus development and as weak as 1:20 for N minus developm ent. In other words, I have altered developer dilution to achieve a constant de velopment time

My standard dilution for a normal negative in my corner of the world is: TMX ASA 50 - HC110 diluted 1:10 from stock solution, developed for Seven minutes at 74 degrees (my tap water in the summer time is between 73-76 degrees) in Pat erson 8x10 trays. Total solution amount is 550mL (Never use less than this amou nt in an 8x10 tray because it will not give adequate coverage of a 4x5 negative) (Factors to consider that may alter the above information slightly; water pH, L ens contrast, stability of electrical current etc.,)

My tests were conducted using a TEN ZONE test target constructed of cardboard an d .3, .6 and .9 neutral density material. This was placed over a vertical light table and read with a 1 degree spot meter. The film was exposed, developed, th en read by a densitometer and plotted. Here is the trick, once you have establi shed what appear to be correct densities under your controlled conditions, SHOOT WITH THE SAME DATA IN THE REAL WORLD. IT WILL ULTIMALEY CAUSE YOU TO ALTER YOU R DEVELOPMENT TIME OR DILUTION.

HC110 is relatively inexpensive when compared to the cost of TMAX developer and the number of negatives a particular amount will develop. I do not like to stan d over my darkroom sink for long periods of time trying to achieve an N+2 or N+3 . The activity level of this developer is such that I can have short developmen t times for all N Plus situations. You must treat HC110 with great respect. If you do not, you will end up with bulletproof negatives that are either difficul t to print or non-printable.

I wear a rubber glove on the hand that will be in contact with the developer (th e 1:10 dilution can cause skin irritation, just think what 1:2 will do, but stil l slightly more safe than pyro relatively speaking)

My Recommendation. Test your desired printing paper first to establish its Cont rast Index or Contrast Range (actually you are testing the contrast of your ligh t source and lens with respect to the paper of choice) and then match your film response to match that of the paper. It makes life very easy when trying to pri nt.

Also take notice of the NEW RECIPROCITY LAWS with respect to TMX. I do not add any additional time for meter readings over ONE SECOND. I expose the film exact ly as the meter reads it (this system works for me, try it ) Overall, HC110 is a very good developer. If you like the look of a printed HC11 0 negative, then hopefully the above information should motivate you to use it. Good Luck!!