‘Show Working Out’ T-Shirt

Just finished a t-shirt – cheap Primark grey – using iron-on transfer paper.  Although this works reasonably well it does leave a film on the shirt and in this instance, as I am printing line drawings rather than coloured in images or photos, a grey on grey effect is seen.  To make a better print I need a single, clean image which is separated cmyk, however, when I did this  (in Photoshop) it was clear that quite a bit of further work is needed, and as this is a one-off there isn’t much point in spending more time.