I have heard that other suppliers of Procion dyes dilute most of their formulas and that Jacquard does not.  So that if you are buying larger amounts of dye, it's most cost efficient to buy the Jacquard dyes in 8 or 16 oz  containers. Jacquard only seems most expensive when you are looking at the 2/3 oz jars. 

I've also read a lot of dyeing websites that recommend carefully calculating the amount of dye you use based on the weight of the fabric, the weight of the dye, and the desired depth of shade. 

On Pro Chemical and Dye's site, they have guidelines for each dye that say something like "Use 4% weight of dye to weight of fabric to achieve this shade". It's usually either 3% or 4%, except for a few pastels that are lower. Like if you have ~ 1 lb/0.45 kg of fabric you should use 0.64 oz or 18 grams of dye.

With Jacquard Procion MX dyes, are there any guidelines about what weight ratio of dye to use to produce a desired shade, especially with the pure dyes? 
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Jacquardmod Jacquardmod
Yes, big savings in the large sizes.

Our recommendations aren't far off from Pro Chem.  You should be able to get a dark color on 1 lb of fabric with 4% of our dye, med on 2lbs(~2%) and med/light on 3lb's(1.3%) of fiber.  It does vary color to color on the pure colors and is true across the board for the mixed ones.  Our Strongest pure colors are Fuchsia, Bright Blue, and Violet I think.  Those are dark at 2%

In reality though things very with differing conditions.  Viscose/rayon/bamboo you want to use 1% more dye on because it takes dye less effectively.  Heat affects some procion colors and not others.  Batching with either black gets a good black, but for an immersion dye needs heat. Warm black(120-140F) requires less than jet black(140-180F).  I often use 6-8% black if i want black as midnight.  I would say that Warm Black is slightly darker.  Jet black is really nice because it is a pure color though, and there is no toning.  

Salt is of course the highly effective way to wring the most color out of an immersion dye with procion.  It's a lot of salt to make a color dark.  It is hard to get deep colors at all with procion unless you batch or use salt.  This is why dye sellers cut their dye with salt.  You don't lose a lot of color, but then your dye has no upside.  With our dye, you can really get extra color with added salt.  Add up to 3x the amount of soda ash you use or ~1 cup per gallon.  I add in 3 additions in 5 min increments.  

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I would also suggest pasting up your dyes- especially reds and violets, with urea. The colors come out brighter and truer to the color chart. I've forgotten to use it a couple of times and couldn't figure out why I wasn't getting the color I wanted- they were just so dull. 
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