Dyed leather is returning to original color??!!

[AmericanSon]

So, I bought some hides and dyed them dark brown and light brown using mainly Angelus pro dyes.  Some pieces were dyed with full 100% dye, some were cut with a reducer.  All are fading back to original color of tanned hide.

This is a brand new phenomenon for me.  I am certain it is the hide.  Just not sure how to remedy.  Thank you in advance for any experience.

Hides.  Chrome Tanned cowhide.  Purchased from a leather lace tannery that closed its doors and moved operations to China.  This was a bulk purchase with about 4,000 lbs. left of full hides and half hides.

Thanks again for any help.

[Mablung]

How did you dye the hides? Airbrush, daubers, etc.? Were the hides sealed before you dyed them? Few more specifics on the hides’ pre-dye condition and your methods would be helpful. 

[AmericanSon]

Thank you.  Dipped dyed the pieces.  Plenty of coverage.  No seal on hides; we soaked them for hours before dye bath.  Can think of anything else but I'm gonna be excited if someone can figure it out.

[Mablung]

Huh. That’s an interesting conundrum. Which is to say, I don’t know what the answer is, although that may simply be because I haven’t tried to dye chrome tan leather; all the chrome tan I’ve dealt with is already colored the color I wanted. Could it be that the chemistry of chrome tanning prevents the hide from holding dyes? I don’t know the chemical makeup of the Angelus pro dyes, but I know the Fiebing’s pro dyes are spirit-based, allowing them to penetrate veg tan more effectively. That tells me there’s some manner of chemical reaction going on there, which may not play well with chrome tannage. 
 

I’m just spitballing/thinking out loud, in case one thought or another turns out to be helpful. 

[AmericanSon]

  On 7/1/2024 at 10:43 PM, Mablung said:

I’m just spitballing/thinking out loud, in case one thought or another turns out to be helpful. 

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Thank you.  I'm hoping that enough spitballers will help me get it figured out.

I believe these hides were from Auburn Tanning before they sold out to China for their lace (not sure what all they are doing now in house)  regardless, they had an entire separate facility that would color the hides.  So, these we not colored in the tanning process.  Anyway, perhaps the clue lies in their process.  I still have a great opportunity with 4000 lbs of cowhide to purchase and I can not seem to get it figured.  

Thanks again for your response.

[fredk]

  On 7/1/2024 at 10:00 PM, AmericanSon said:

Hides.  Chrome Tanned cowhide.  Purchased from a leather lace tannery . . .

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That thar is a clooo.

Chrome tanned, in my experience wont take a dye and keep it unless it has been treated beforehand. I use cellulose thinners to prepare chrome tan. Also you are using a water-based dye. I use an oil -based dye on chrome tan

[AmericanSon]

Thank you Fred.  I think both the pro from Angelus and the feibings are both alcohol based dyes.  But I am interested in the cellulose thinners you use to prepare the leather.  Can you tell me more?  Thank you.

[AmericanSon]

Here's the feibings I used and the pro is the same if I'm not mistaken.

[fredk]

Alcohol based can still be thinned and washed out with water

I simply give the chrome tan a good wetting and washing with the cellulose thinners and whilst its still damp I dye it

[Wepster]

https://en.wikipedia.org/wiki/Lacquer_thinner

AKA cellulose thinner