Shirt color change with WB cure

[Du Manchu]

Rookies at WB/DC here and spoiled a 60 shirt job job today.  Need some advise in prep for the reprint.   1c WB gray on a Dark Heather Canvas 3001cvc (52/48 cotton/poly).   Folded them in half on the dryer with sleeves in and they shifted darker towards a brown hue, top-side, permanently.  Once laid flat, the scorch was very apparent.  The tags were not crispy.  Curiously, some of the first shirts on the belt, laid flat shifted completely, shifted both sides, top and bottom evenly.   All sizes shifted so they may rule out a dye lot problem.    Maybe just too hot, too long for a heather, or are heathers just scary shirts to WB?  However, we did this same shirt WB last month in heather blue and no color shift.  Humm.

Sprint 3000 with 8 ft or heat
Original spoiled  run, 355 degrees at 2.5 min
2nd test run, laid flat to scorch the rest of the shirt, 325 for 1.5 min.  (shifted, but not quite as much)
3rd test run, laid flat to scorch the rest of the shirt, 355 for 1.5 min (same scorch level as original)

What temp and time would be a good starting point to run some cure and wash tests?   

Thanks in advance for the pointers.

[Maxie]

After a day or two do the shirts look the same?    Sometimes the heat caused a dye color shift that corrects itself when the shirt cools down.
I would try another shirt company, at those temps and times the colors should not change.

[BP]

yeah just let them cool down.

[Du Manchu]

I wish.  Not like red shirts.  These are cooked and darker.  We could have probably passed just run them back through and evened out the color, but unfortunately, the ink color was just a few shades darker than the shirt, and the color shift was towards the ink color and made the logo hard to see.   

[Rockers]

Back in early 2000 when American Apparel were the new kids on the block we had a few hundred spoiled tees. They so changed color in the dryer and never recovered. I think those were as well poly cotton blends.
Of course they refunded us.

[ericheartsu]

that dryer setting (granted i don't know your dryer setting) seems super high.

We typically run discharge jobs no higher than 340, and usually 120-140 seconds inside the chamber.

If it's a single color WB shop on that poly cotton tee, you probably needed to be around 320 for 2-3mins. This is also effected on how your ink is built, and what additives are the ink.