V. Read the following paragraphs and discuss the advantages and disadvantages of other methods of origination

IV. Compare line origination and halftone origination.

Scanning

Principles, filters, beam, produce, separation, positives, laser, speeds, scanner

I. Read the sentences and say if they are true or false. If they are false, correct them.

1) To be reproduced line original is placed on the copy board of the process camera.

2) Copy board is coated with a light-sensitive emulsion.

3) The developed negative can be used for platemaking

4) Line origination is used to produce a halftone negative or positive from continuous-tone originals.

5) Halftone effect is obtained by placing a 'screen' in the back of the lens.

6) Good halftone reproduction depends on the density range.

7) The effect of full colour has to be achieved in printing by breaking the original picture down into three components, corresponding to the three basic colours.

8) Any colour can be reproduced from combinations of four colours.

9) Magenta, yellow and cyan are therefore known as primary colours.

10) Masks are used to correct colour casts or to compensate for the limitations of the process.

II. Find the equivalents of the following terms:

1. copy board a) експонування

2. colour separation b) ступінь насиченості

3. magenta c) негатив

4. light-sensitive emulsion d) фотомеханічне переведення

5. mask e) грунтовка, перші шари фарби

6. fixing solution f) голубий

7. shadow dots g) кольоровий відтінок

8. ‘subtractive’ primaries h) виготовлення форми

9. halftone negative i) кольороподіл

10. density range j) пурпуровий

11. flat copy k) розчиняти

12. to dissolve l) тримач оригіналу

13. PMT m) розчин-фіксатор

14. exposure n) світлочутлива емульсія

15. platemaking o) маска

16. cyan p) непрозорий оригінал

17. colour cast q) растрова точка в тіні

III. Fill the gaps using the following words:

Most colours … is now done using electronic scanners. These use the same … as conventional separation but work at much higher …, give superior quality and can … all four colours at once. They use a high-intensity light or a … beam to scan the original; colour… and a computer are built into the … to convert the signals picked up by the … into screened negatives or … for each of the four colours.

Tints Where a flat area of colour is required, this is normally produced by the reproduction house using tints. A tint is not solid" ink, but made up from dots of the three process colours — yellow, magenta and cyan (black can also be used). The tint required is selected from a tint chart, which can be obtained from the reproduction house or printer, The client specifies the colour in percentages of yellow, magenta, cyan and black in this order, for example 90Y + 30M + 20C+ 10B.

Dot gain The term 'dot gain' describes an increase in the dot-size that can occur when printing takes place. Normally the dot on the film can be reproduced at almost exactly the same size on the metal printing plate, but in the printed version the size may have increased. This is a result of various factors, including the blanket, the machine, the inks and paper being used.

Under-colour removal Where a subject has a dark area, the four-colour process will normally reproduce this using large dots of all four colours, whereas an identical effect can be achieved using only one or two colours. When heavy dots of all four colours overprint each other, there are drying and other problems, and more ink is used than is necessary, To avoid this situation, the scanner can be set to remove most or all of the magenta and yellow in the dark areas, leaving mainly black, sometimes with some cyan to improve the density.

Дата добавления: 2014-12-23