Missing Tips

Photopolymer or mag plate?

If you change the orientation of the plate does the problem move or go away?

It’s Photopolymer, freshly put on the base, the missing edges seem fine on the plate under a magnifying glass, they look like they are getting no ink though. Unfortunately the plate is too big to run vertically.

Should I try lowering my rollers if the tips are missing ink, I’m worried about over inking the whole thing?

Just some thoughts off the top of my head:

Are you able to move the plate to a new location in the chase or is it filling your printable area? Or alternately, can you rotate the entire chase to put the plate in the opposite corner from where you have it now? If you can, try positioning it differently to see if that makes a difference.

Other possibilities might be: is your base truly flat? Is your press’s bed truly flat? Are your rollers true-to-diameter across their lengths or have they swelled or shrunk anywhere along their length?

You can check the first two with a known-straight edge like a good quality steel ruler without nicks or bends. Lay it edge-on upon each surface and, with a light source on the far side of the straightedge from you, slide the straight edge across the surface lightly while looking for light between the two. Be careful not to scratch things, though!

The rollers can be checked with a micrometer. Set it at one end and check against that set measurement along the length of the roller. Turn the roller and check again several times as well to make sure it hasn’t gotten out of round anywhere. Again, be careful not to scar your rollers.

A final thought would be, how hard are your plates? Perhaps they’re too soft and the rollers are distorting them somehow?

if you dab ink on the H with your finger or hand roller does it print all of it, if not try putting a sheet of paper behind the forme this will alter your impression but also raise the plate to your rollers and if you can look at your rollers after going over the plate you should be able to see an outline of where it has taken ink off, you may have to lower your rollers or try another sheet of paper to find out, John.

Thank you mephitis and John, I tried a number of these suggestions, in the end I lowered the rollers and it all came good. I’ve come to the conclusion my Roller Height Gauge which is one of the block ones that sit flat on the press bed, is not so accurate. Now the rollers really grip the gauge instead of just leaving a ‘thin film’ of ink as I was told to.

But with the extra roller pressure the tips of all my plate became inked without over inking the rest……so I’m happy.

Maybe I need to order one of the round lollipop style gauges that everyone else seems to use.

Many thanks for the help, I’ve learned so much in the last few days and mostly from you kind fellows here.

Nick.

Nick and those who have provided helpful comments have illustrated a good lesson.
It all starts with correct inking
No matter how much you mess with the packing nor how much you curse and wave your arms, it just will not work well until you get the inking right. Often removal of the chase to the stone and inspection with a magnifying glass will yield good information.
It all starts with correct inking.

inky that is exactly what I have concluded and got there by taking a work light to the press with a magnifying glass to see what was actually happening.

There was certainly quite a bit of cursing and arm waving as well though ;-)