Black background turns out dark brown on rock slate

[3twenty6]

Hello everybody
Just joined today and would really appreciate some advice here. I've just tried to print a rock slate from Coralgraph using a Ricoh 3300n with Sawgrass inks with Truepix paper. The image has a solid black background. Printed face down for 8 minutes at 202C with a firm pressure as advised on this forum but the background came out more like dark brown than black with the white type looking slightly brown, not white like it should be. Is this due to cooking for too long or should I increase the time even more or is it simply that I am being too ambitious to get a solid black colour and it can't be done with this product? The previous slates I have printed have been fine but they have been photographs. I don't pre-heat the slate btw. Any suggestions gratefully received.

[bms]

Browning blacks are due to over cooking so I'd lower your temp to 190.

[AJLA]

Ditto what Martin says, with the Ricoh you do have to do a bit of adjusting. Works a treat when you do.

[3twenty6]

Hi BMS and AJLA. Many thanks for your replies. Sorry not to have responded sooner, I've been away for a few days. I tried a few times and eventually got a much better result printing at 190C for 6 minutes. It still wasn't jet black but a lot better than the first one. Anyway, customer was happy which is what matters the most!