I am trying to wrap my brain around the DOS column on the chart 'Dyeing Trials for 5R 4/12' in the July 15th Power Point presentation.  The Munsell notations for my Fuchsia and Scarlet dyes show they both increase in chroma as the DOS deepens.  On the chart the 3.0% DOS dye bath is predicted to result in a chroma of 11.  The 2.6% DOS dye bath is predicted to result in a chroma of 12.  Wouldn't the chroma decrease if the DOS decreases for a dye bath using these two dyes?  (We've demonstrated that some dyes have higher chroma at lower DOS.)

Also to confirm my calculations for a 3.0% DOS trial for 5R 5/12 (this is the color notation on my Munsell color wheel):

WOF 5g

DOS 3.0%

200ml water (40:1)

Total Dye 7.5ml of 2% stock

67% Scarlet - 5.025ml

33% Fuchsia - 2.475ml

From Chart:  2.8g of soda ash dissolved in 50ml of the water

                   12g salt

Comments

Mary Rios (not verified)

Hi Anne, while i don't have an answer to your question, i have a question for your DOS of 3%. do you mix both colors using a dos of 3% or because you're using approx. 1/2 more of the scarlet is it like 2% dos for scarlet and 1% dos for the fuchsia?

this is the area that i never understood in the last class - i actually had a different forumula - but want to understand this formula... : )

 

Anne Vincent

Hi Mary,  Part of what I am trying to understand is the formula.  I think it is that the overall formula for the first trial dye bath is a 3.0% depth of shade.  With the scarlet at 67% that would mean it was 2/3 of the dye in the dye bath, and so 2/3 of the total DOS or 2.0% DOS.  The fuchsia is the remaining 1/3 of the dye in the dye bath, and so 1/3 of the total DOS or 1.0% DOS.

The second trial on the example is 2.6% DOS with the scarlet and fuchsia in the same proportion of 67%/33%.  If my calculations are correct, then the scarlet is 1.74%DOS (still 2/3 of the total DOS) and the fuchsia is .86% DOS (still 1/3 of the total DOS).

I think deciding on the DOS to try is the educated guess part based on the value and chroma numbers compared to the target colors.

I could be totally wrong, if so, these first 3 trials will be something to see! 

Karren K. Brito

Mary, the formula with total DOS =3% gives 5.0mL scarlet and 2.5mL of fuchsia.   The second formula, to get the same color for the same WOF has to give the same answer.

Let's check that it does. 

Formula: DOS scarlet 2.0%, DOS fuchsia 1.%

Calculations: WOF x DOS/stock = mL of stock

  scarlet:        5g   x  2.0%/2.0% = 5mL

fuchsia:          5g   x 1.0%/2.0% = 2.5ml

Reguarding the estimated chroma- Remember I was changing the numbers in the powerpoint presentation as we spoke, not sure what numbers got recorded but will go check shortly.

The second formula allows us to use our spread sheet of pure colors.

Scarlet DOS 2%--7.5R 6/18

Fuchsia DOS 1% ---7.5 RP 5/12

So I think that the chroma of the mix will be less than 18 and more than 12 but closer to the scarlet than the fuchsia because there is more of it, so let's guess 16.  But then taking into consideration that mixing two colors dulls the chroma a bit, I'd revise my guess to 15.

This would be too high of a chroma for our target color.  I have thought up two diffferent schemes for reducing the chroma of the mix; 1.) reduce the DOS -this will also increase the value(lighten) of the mix, 2.) exchange the fuchsia, which is adding blue to the mix, for a very small amount of a low chroma blue, navy-- this may darken the mix a bit.

I don't know which will work better so I'm going to try both.

 

 

Anne Vincent

I have the first 3 trials in the dye bath now.  The proof will be in the chips, but I can tell already just 2% of the navy in the dye bath significantly lowers the chroma.  I'll post the results later today.

Karren K. Brito

It is amazing how we can not see the color until we make the chips, even if they are small, Anne.

Looking forward to see them.