Troubles with developing Tri-X

[DsrtBill]

There may be some rare exceptions, but all of the charts from the chemistry manufacturers that I have seen usually give the same times for 135 and 120 film, all other conditions beuing the same.

Alright, perfect, thanks.

It is a minor point, but consider your notation representing your dilution, "1:50"
To me, that notation is somewhat ambiguous because it can be interpreted to mean either, 1 part of A combined with 50 parts of B, in which case you end up with a final volume of 51 parts. In photography this is the usual meaning. However, I worked in a clinical lab where dilutions were assumed to represent a ratio of the part to the final volume, so 1+49. I think it is safer to use the notation "1+50" to avoid confusion.

To be honest, I have no idea why I started to use 1:50 instead of 1+50. All of my written notes are in the 1:50 format, however incorrect that may be. I have seen 1:50 and 1+50 used interchangeably, so I assumed that they meant the same thing. I do not believe this to be that big of an issue, but if it can cause issues later on, I'll use 1+50/1+25, etc., henceforth. All of the calculations were done as 1+24, 1+49, etc.

The word "beaker" can refer to several different types of glassware, and some beakers do have markings on them to represent volume. However, I would not consider most beakers to be very good for measuring, except for very rough approximations. Notice this 50mL beaker warns that the markings are "APPROX"

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For measuring Rodinal, I would recommend a graduated cylinder, possibly one that holds 10mL, total -- or possibly 25mL? You want the smallest size that can contain the largest volume you would normally need to measure. If sometimes you need to measure less than 10mL and other times more than 25mL, then I would consider getting two graduated cylindars, maybe a 10mL and a 50mL or 100mL.

This is another example of where my greenness is showing; I still do not know all of the accurate terminology for lab equipment. For measuring Rodinal, at the moment, I'm using a cheap graduated cylinder. I have no traditional lab training, so apologies for using the incorrect name.

The manner in which I'm mixing the Rodinal "one-shot" is: pour about 500ml of distilled water into a 1000ml beaker. Next, I measure 40ml, then 44 ml, in a 50ml cylinder to get ~588ml in the 1000ml beaker. After that, I measure out 10ml of Rodinal concentrate in a 10ml cylinder, and then 2ml of Rodinal concentrate in the same 10ml cylinder. This gets roughly to the 600ml I'm going for- I am in no way suggesting this method.

As mentioned in post #30, I broke my 25ml cylinder.

I understand this is more than likely not a perfectly accurate way of measuring this type of thing out, but I am using what I have. I've been contemplating getting a glass pipette or measuring syringe, if you happen to have any words of wisdom on that front.

Sorry if that sounded defensive. If you have suggestions for better quality beakers/cylinders or other measuring graduates(?), do share.
- Bill

 

[runswithsizzers]

All of my written notes are in the 1:50 format, however incorrect that may be. I have seen 1:50 and 1+50 used interchangeably, so I assumed that they meant the same thing.

Using 1:50 is not "incorrect" -- only somewhat ambiguous. You "assumed that they meant the same thing," but someone else might assume somesthing different. No big deal among photographers, nit-picking really. But in some other context it could be an issue.

For measuring Rodinal, at the moment, I'm using a cheap graduated cylinder. I have no traditional lab training, so apologies for using the incorrect name.

No apology needed. Every craft has it's own technical language, and it takes time to learn it. It sounds like you are on the right track towards success.

 

[MattKing]

To be honest, I have no idea why I started to use 1:50 instead of 1+50. All of my written notes are in the 1:50 format, however incorrect that may be. I have seen 1:50 and 1+50 used interchangeably, so I assumed that they meant the same thing. I do not believe this to be that big of an issue, but if it can cause issues later on, I'll use 1+50/1+25, etc., henceforth. All of the calculations were done as 1+24, 1+49, etc.

The traditional USA Kodak method uses 1:50, as do some other areas outside photography.
Usage seems to vary a bit as well depending on geography.
Notionally it means one part of Rodinal in a total volume of 50 parts.
For communication purposes in an international forum like Photrio, the notation 1 + 49 is probably better.
In the case of 1:50 meaning 1+50 vs. 1+49, it matters little.
But in the case of 1:3 meaning 1+2 vs. 1+3 the difference is significant.

 

[MTGseattle]

Well crap. This thread now has me questioning my methods. My interpretation of 1 to 50 is 500ml (single roll) broken into 50 parts total.
10ml rodinal to 490ml water.
If this is incorrect lab procedure, I'm going to stay incorrect as I don't notice anything weird except grabbing a used bottle of fixer the other day which resulted in a dilution of a dilution.

 

[koraks]

10ml rodinal to 490ml water.

That's correct.
Note that 10ml rodinal + 500ml water would amount to virtually the same, so don't worry about it either way.

 

[MattKing]

Well crap. This thread now has me questioning my methods. My interpretation of 1 to 50 is 500ml (single roll) broken into 50 parts total.
10ml rodinal to 490ml water.

Your method is fine - it is one very common (particularly in North America with Kodak products) approach to interpreting 1:50.
And as @koraks posted, it really doesn't differ effectively than the alternative, when you pick that example.
The only issue is with ratios that are more concentrated, and really the only issue is that different interpretations make "communicating" information more difficult/uncertain.