Eastern C, eh? I like that method, too and also use the combined C method or even the E method.
If you're mixing methods in the same project over stockinette, there will be a ridge line. Ask me; I did it! @@ps! LOL!!
So, if that's what you've got going, choose one or the other and stay with it.
The only time I mix methods now is if I can't get 3Ptog in the C method, then I swicth to the E and just for one stitch.
If you're a young knitter, or just recently switched to C or EC, then your tension will even out in time where you could do more mixing of methods.
To be safe, though, stick to one method when doing stockinette or even reverse stockinette and this should eliminate the ridge lines.
My ridge lines, BTW, looked like waves or ripples in a pond. I left them as the flamingo embossed into the pattern appeared to be feeding in water. I took contracting pink yarn over pink flamingo pink and laid in French knots every few stitches to make it appear that birdie was eating (pink) shrimp! LOL!
I am knitting a sweater using 3ply bulky yarn and size 10 needles. I have a definite ridge look on the front. Every other row is definite. I have tried using a size 9 and size 8 needles in the k and/or p row. I have also switched from the English to Continental/Eastern style. All to no avail How can I knit and have a nice even stockinette? Thanks in advance for your help.