The Holga camera produces its special effects because it is poorly made - light leaks, inaccurate shutter speeds, poor quality lens, etc.. No two of them will produce the same effect. There is a cult following for this camera. Some serious photographers use them more as a toy than anythinng else.

Special photography effects are seldom done "in camera". There are a few screens, and mattes with different shaped holes available for some models of film cameras. These are placed on the film rails in front of the film.

Special effects are usually done with filters that are placed in front of the lens. There are far too many of them to list. Use your favorite search engine to discover them. These filters are 2 basic types: those that screw into the front of the lens barrel; those that are mounted into an adapter that is screwed into the lens barrel. These filters can be used on all DSLRs as well as film cameras, because the lenses for a DSLR camera lens have threaded lens barrels just like film camera lenses. The filter manufactures I am most familiar with are: Cokin, Hoya, Tiffen - there are others.

There are 2 basic types of filters: colored; spectral. Colored filters work best with positive films (slide film), b&w negative film or with a manually set white balance for digital cameras. Spectral effects such as image splitting or star effect work well with all film and with auto or manual white balance.

There are 2 film types: positive image; negative image. Both are available in color or b&w (b&w positive film is difficult to find). Positive image film is usually called slide or transparency film. Prints can be made from transparenies. Negative image film is usually called print film. Prints can be manipulated in a number of ways in the darkroom. You'll need to get a book and read about it, as it is far too involved a topic for this venue.

Each manufacturer balances the color temperature (expressed in degrees Kelvin) to what they consider best degree of warmth /coolness for the various types they make. Each of the films will also have different color saturation levels - depending on whether the film is intended for family snaps, weddings, scenics, sports, etc. Film manufactures have brochures available at photography stores and their webs site describing each film. The manufacturers I am most familiar with are: kodak, Fuji, Ilford, Agfa - there are others.

The phraseology of your question and your amplifing information lead me to believe that your knowledge base of basic photography, either digital or film, is minimal at best. I've tried to give you a start here. I think your best approach is to go to a book store, peruse their Basic Photography book section, choose one, read it then go from there.

Photography is a rewarding hobby. I know, because I been doing it for 4+ decades. But like all things, excellence requires effort. You'll make a lot of friends on a journey into the hobby. Photographers are a happy lot and are willing to share their experience - so join a photography club.

Good "Hunting".

Check out the OptikVerve Photoshop plugin software. It allows you to apply different types of film effects to digital images.