Computer-to-plate (CTP) Operator Interview Preparation Guide

Computer-to-plate (CTP) is an imaging technology used in modern printing processes. In this technology, an image created in a Desktop Publishing (DTP) application is output directly to a printing plate.

Agfa Advantage DL violet laser fotosetter with VPP68 plate processor
This compares with the older technology, computer-to-film (CTF), where the computer file is output onto a photographic film. This film is then used to make a printing plate, in a similar manner to a contact proof in darkroom photography.

☛ Transfer images from master plates to unexposed plates, and immerse plates in developing solutions to develop images.
☛ Examine unexposed photographic plates to detect flaws or foreign particles prior to printing.
☛ Lower vacuum frames onto plate-film assemblies, activate vacuums to establish contact between film and plates, and set timers to activate ultraviolet lights that expose plates.
☛ Examine finished plates to detect flaws, verify conformity with master plates, and measure dot sizes and centers, using light-boxes and microscopes.
☛ Perform close alignment or registration of double and single flats to sensitized plates prior to exposure, in order to produce composite images.
☛ Remove plate-film assemblies from vacuum frames, and place exposed plates in automatic processors to develop images and dry plates

☛ Enter, store, and retrieve information on computer-aided equipment.
☛ Enter, position, and alter text size, using computers, to make up and arrange pages so that printed materials can be produced.
☛ Maintain, adjust, and clean equipment, and perform minor repairs.
☛ Operate and maintain laser plate-making equipment that converts electronic data to plates without the use of film.
☛ Examine photographic images for obvious imperfections prior to plate making.
☛ Operate presses to print proofs of plates, monitoring printing quality to ensure that it is adequate.
☛ Monitor contact between cover glass and masks inside vacuum frames, in order to prevent flaws resulting from overexposure or light reflection.

☛ Position and angle screens for proper exposure.
☛ Inspect developed film for specified results and quality, using magnifying glasses and scopes; forward acceptable negatives or positives to other workers or to customers.
☛ Punch holes in light-sensitive plates and insert pins in holes to prepare plates for contact with positive or negative film.
☛ Unload exposed film from scanners, and place film in automatic processors to develop images.
☛ Place masking paper on areas of plates not covered by positives or negatives, in order to prevent exposure.
☛ Mount negatives and plates in cameras, set exposure controls, and expose plates to light through negatives in order to transfer images onto plates.
☛ Operate and maintain a variety of cameras and equipment, such as process, line, halftone, and color separation cameras, enlargers, electronic scanners, and contact equipment.
☛ Perform tests to determine lengths of exposures, by exposing plates, scanning line copy, and comparing exposures to tone range scales.
☛ Mix solutions such as developing solutions and colored coating solutions.
☛ Activate scanners to produce positive or negative films for the black-and-white, cyan, yellow, and magenta separations from each original copy.
☛ Select proper types of plates according to press run lengths.
☛ Reposition lamps and adjust aperture controls in order to provide high quality images.
☛ Analyze originals to evaluate color density, gradation highlights, middle tones, and shadows, using densitometers and knowledge of light and color.
☛ Set scanners to specific color densities, sizes, screen rulings, and exposure adjustments, using scanner keyboards or computers.
☛ Perform minor deletions, additions, or corrections to completed plates, on or off printing presses, using tusche, printing ink, erasers, and needles.
☛ Correct minor film mask defects with litho tape or opaquing fluid.
☛ Position color transparencies, negatives, or reflection copies on scanning drums, and mount drums and heads on scanners.
☛ Arrange and mount typeset material and illustrations into paste-ups for printing reproduction, based on artists' or editors' layouts.
☛ Scale copy for reductions and enlargements, using proportion wheels.

CTP methods differ according to the construction type of the imagesetter and the light source used to expose the plate surface. In terms of construction type there are three different kinds: internal drum, external drum and flat-bed imagesetters. The two main light sources used to expose the plate are ultraviolet light lamps and laser diodes. The wavelength and energy of the laser diodes depend on the type of plate that is used. This technology is mainly used in newspaper and magazine printing

In an internal drum image setter the plate is put into a cylinder, while the imaging head moves along the axis of the cylinder to expose the plate. The rotating mirror at the end of the imaging head rotates around its axis to beam the laser on the desired part of the fixed plate. The construction type makes it more difficult to use several lasers at the same time, but just using one laser also has advantages such as uniform beam intensity over the whole plate.

The plate is wrapped around a drum that can rotate around its axis, while the imaging head that projects the image on the plate can move along this axis to focus the laser beam on the surface. The simple construction type makes it possible to arrange multiple image heads next to each other and use them simultaneously. This leads to a decrease of the imaging time needed to expose a whole printing plate

The image is reproduced line by line on a fixed flat printing plate by a laser beam that is deflected by a rotating polygon mirror and then onto the printing plate. Because of the setup the laser beam becomes less accurate at the edges of the printing plate and is therefore mainly smaller formats or production with lower quality expectations.

A company will want to see how much you know about company culture and whether you have an understanding about the company culture. For example, if the company emphasises on integrity with customers then you should mention you would like to be in such a team because you believe in integrity.

If however, you are aware that the company values do not fit your thoughts then be honest. The best policy is to be honest with yourself.

☛ At CTP Thermique we work with some of the largest scale machinery in our industry. Tell me about the types of machinery you are most experienced with.
☛ We put a lot of effort into ensuring CTP Thermique uses only the best parts and materials available. What do you know about our cutting edge machinery?
☛ How will the knowledge gained from your most recent position help you succeed in this role with CTP Thermique?
☛ The health and safety of our employees is top priority at CTP Thermique. How would you react if your supervisor asked you to perform a task that you were not comfortable with?
☛ At CTP Thermique we measure productivity in a variety of ways. In your opinion, what are the most important performance metrics for this position?
☛ Our reputation is very important to us. In which ways do you feel CTP Thermique stands out from the crowd?
☛ Some of our competitors use social media to promote their brand. How do you feel about the social media presence at CTP Thermique? Do you feel this type of marketing is relevant to our industry?
☛ Our motto at CTP Thermique is to work smarter, not harder. If you had a workplace motto, what would it be?
☛ We have a variety of shifts at CTP Thermique. Do you have any restrictions on your availability?
☛ Do you have experience working in a unionized environment? What are your thoughts on union based roles?
☛ Tell me about a time that you have helped a co-worker accomplish an important goal.
☛ What was the biggest change you have had to deal with in your career?
☛ Tell us about a time when you were particularly effective on prioritizing tasks and completing a project on schedule.
☛ What are your career aspirations beyond this job?
☛ Why are you the best candidate for us?
☛ How would you describe your written communication skills?
☛ How would you describe your relationship with your customers or clients?
☛ Name me a few things you were asked to do in your last position that you weren't trained for.
☛ When have you had to think outside of the box to solve a problem?
☛ If you were given a choice, which work related task would you leave for last? Why?
☛ Tell me about yourself.
☛ With your experience, what contributions do you believe you will make to our department?
☛ On a scale from 1 to 10, how honest are you?
☛ How can we motivate you on the job?
☛ Give me an example of a time when your communication skills helped you be a more effective leader.
☛ When have you effectively delegated tasks to your employees?
☛ How do you handle situations that could cause you to be late or miss work?
☛ What types of activities keep you busy, outside of work?
☛ What makes you a great problem solver?
☛ Is compensation the most important factor for you when taking a new job?
☛ What part of this career brings you the most stress?
☛ Tell me about a time there was a serious conflict. How did you resolve it?