Portrayal is a description of someone or something in a particular way; a representation.In research it is  the act of showing or describing someone or something especially in a painting, book, etc..A presentation is the process of presenting a topic to an audience. Display something with the help of audio-visuals and narrative to the audience. It is typically a demonstration, lecture, or speech meant to inform, persuade, or build good will. The term can also be used for a formal or ritualized introduction or offering, as with the presentation of a debutante.

It would help if we could read the actual sentence/paragraph in which you read these terms.  I agree with what Ravi said, but there could also be other subtle meanings, depending on just what the paragraph says.

in my opinion portrayal will be your take on the issue whereas presentation will be closer to reality

Hi,

Just another take on this. For example the portrayal and presentation of women in advertisement through content analysis.

The presentation will come first before the portrayal. If no women is being presented in your sample, there will be no basis of analysing their portrayal. The presentation will actually mean that this group is presented in your sample.

Portyal of the presented women in the advertisements will therefore consider if they are portrayed as housewives,cooks or sex object.

Another recent example is the Oscars. If there are no black actor in the list of nomination, there will be no need to analysing their roles in the films.

Hope that helps.

Dear Emmanuel Mogaji,

What i understood from your point of view, presentation is something objective, i.e. the extent to which a certain variable or entity is present in a population or sample, whereas as portrayal is a construction of that entity in your population or text. am i right? 

Hello Ess,

That's actually my point. The presentation can even be quantified, it's an extent of the presence of the variables while portrayal is how you constructed those presentation.

Best Wishes

Thank You Emmanuel Mogaji

Portrayal and representation (e.g., social representation) are the same.

It may be that you mean "portrayal" and "representation" -- and those are very similar in meaning. I have tended to use portrayal for people and places - and representation for bigger concepts or constructs, but it may just be a matter of taste or style in terms of how one uses it. Presentation -- might be how a media outlet is putting forth some message or information. 

Presentation is a very vague notion, and for research purposes you should look at literature around"framing" which will refer to representation. Portrayal of something/someone falls closer to this notion.