The papers of the '67 issue are softer and slightly grayish, while the papers of the 3c 1861 are harder and more of a pale white.
The 3c 1867 only comes in two printings, Claret and Rose Brown. The Rose Brown may be a hold-over as it's very similar to the 3c 1861 Rose Brown printing of '66.
The claret's are a recent study of mine, and are most curious. I can post pictures if anyone is interested.
The 3c 1861 was printed in Rose Claret over 1864-65, but the range of color is way different. The deeper shades are more of a grayish claret, harkening (sp) back to the scarce Grayish Claret of the 1851 Issue. Here it's the rose hue coming through, and that's what makes this color so distinctive. The medium and paler Rose Clarets are somewhat bland, ranging closer in shade to the Dull Red printings of '65-66.
Now, the deeper 3c 1867 Claret is a very fruity color, almost like a Pinot Noir. And, the medium and pale Clarets are also much richer shades. The pale clarets, in particular, approach some of the brilliant shades of the 3c 1851 pale claret. For claret lovers, these grilled issues make a great study!