Registration for trade work and the pitfalls for foilers.

Colour bar misalignment, actually supplied like this

Cling wrap affecting gripper and side lay and unstable stacking of one pallet on another

Print Production

Hot Foil stamping and embossing are carried out after printing.  So lets take a typical scenario.

A four colour job is printed onto an uncoated offset sheet 300 gsm. A large solid is printed over most of the sheet.  The sheet is fed into the press and pushed or pulled to the side lay where the grippers grab the sheet and take it through the press. Four colours or more are then laid down in perfect registration with each other and the sheet is delivered at the other end.

When the stack is full the pile is removed and set aside for drying and later finishing.

This printed material then finds its way to the trade foil stamper probably two, maybe more, days later.

The trade foiler  unwraps the print and loads the sheet into the foil stamping press hoping to use the same gripper and side lay and then register the foiled image with the printing.

In fact there are registration issues and the foil does not register with the print. Here are the possible reasons why:

1  The gripper and side lays are not marked on the sheet so the foiler has to call the printing company.

2  The printing is moving on the sheet. The colours register together but the image is changing position on the sheet. The side lay may not be working and the sheet maybe bouncing out of the grippers.  This is obvious by the colour bars or side lay marks not falling in a straight line down the sheet on delivery.

3  An uncoated sheet with a large ink solid will expand or contract as it dries or with changes in atmospheric humidity.

4  The stock was cut down but the gripper was not pushed up against the back stop or the pile was not jogged up resulting in uneven cuts

5  The clamp on the guillotine was too light resulting in an angled cut so the registration comes in and out with each batch cut.

6  The pallet was not secured with straps or protected with cling wrap and the straps bite into the stock on the gripper and side lay.

7  Cling wrap only was used and wrapped tightly causing the sheet edges to bend up or down making pick up and feed on the foiling press difficult.

Studio

8  The image for the foil has not been “trapped” in the studio so there is no choke meaning the registration is hairline and a slight movement will expose white areas or the underlying colour.

9 The foiled image was “reversed out” of the background leaving a very tight area on which to place the foiled image. Better to let the foiling fall on top and set the image to “overprint” , then if there is a slight movement in the sheet it will never be noticeable.

Please heed these points for the trade foiler

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