Titanium Oxalate was introduced in the tanning industry as a more environmentally sound alternative for chrome.  
By creating stronger complexes between the fibers and the dyes, titanium mordant improves lightfastness and wash-fastness. The special quality of this mordant is that it has a strong orange reaction with tannins, and as such it can give beautiful oranges in eco printing, and brings out orange with oak gall tanned fabrics, and with weld.
 
Recommended method of use;
 
For protein; mordant at 7-10% WOF and then use with a prepared dye bath.
For cellulose; make a regular tannin bath and aftermordant with 5% WOF Titanium Oxalate. Yellow dyes on cotton;  mordant with aluminium acetate, dye with natural dye and use Titanium Oxalate asa post mordant to modify the hue of the dye. 
Why is this? Cotton forms a better bond with tannin than it does with titanium oxalate. If you first mordant with titanium oxalate, the reaction with the tannin will be less strong than when you first tan the fabric and then simply soak in a cold titanium oxalate solution of 5%.
 
Do not let a Titanium Oxalate mordant bath come to a boil, keep below 85ºC. I recommend disolving the powder with warm water and doing a cold mordant overnight.
 
Potassium Titanium Oxalate, also known as Titanyl Potassium Oxalate, CAS number 14481-26-6. Titanium oxalate is a very fine powder and  should be used with a mask and gloves. Store away with clear labeling from children and pets.