(i) Spirit Duplication.
(ii) Ink Stencil Duplication.
(iii) Offset Lithographic Machine.
(iv) Photocopying Machine.
Spirit Duplication:
(1) It can reproduce documents in colours.
(2) It is a direct process as their masters copy come directly with copy papers.
(3) It is simple to operate.
(4) It can use spirit instead of ink.
Stencil Duplication:
(1) It is also a direct process.
(2) It is simple and easy to operate.
(3) It makes use of ink.
Offset Duplicating:
(1) It can produce up to 6,000 copies of documents.
(2) It is a direct process.
(3) It produces in a clear and legible form.
(4) Metal or plastic plates can be preserved for future uses.
(5) It is a cheap method of producing high quality work.
Photocopying Machine:
(1) It produces exact copies instantly.
(2) The machine is capable of reducing the sizes of papers.
(3) The machine saves time.
(4) There is no limit to the number of documents that can be produced.
