Room darkening Roman Shades are an interesting blend of curtains and blinds. They are typically made of fabric, which is more like curtains than blinds. But they mount closer to the window than curtains, and in that way they are more like blinds. They also retract up, like blinds, rather than to the sides like curtains.
Not all Roman Shades (which are sometimes called "Country Curtains" or "Roman Blinds") are designed to be room-darkening. In fact many of the models available are translucent. Some are even made of bamboo strips, which allow light to pass through them.
When choosing the shades, the first thing to be aware of is the measurements of your window. Because they fit inside the window frame, unlike curtains, the measurements need to be precise. In addition to measuring the width, you also need to measure the height of the window, since Roman Shades are designed to unfold down to full length. (It will look odd if they are too long and you need to keep them partially folded up.)
For room darkening Roman Shades, you should avoid any of the models with bamboo or wood. Look for heavy fabric material, which folds in either "waterfall fold","flat fold" or "hobbled fold". The heavy material may sometimes be labeled as "insulated". These do a better job of blocking light than room darkening curtains, because they fit inside the window frame, which prevents "leakage" of light around the top and bottom, which is common with curtains. Consider this if you do not need the elegance of full curtains. (Roman Shades do sometimes look a little odd because of how they fit inside the window frame, rather than covering the whole window.
The models with the separate backing are also described as "thermal" shades, and they actually have a separate backing adhered to the window-side. Not only does this completely block the light, but these types of window treatments keep the house cooler in the summer (by keeping the heat out), and warmer in the winter, by insulating the windows and preventing heat loss.
You can find these types of shades for as little as $30 or as much as $300. Because of the wide arrange, it is recommended to do your shopping online. Be sure to compare all aspects of the purchase, including presence or lack of a backing, shipping costs, etc. Look for sites that allow customer reviews to help you watch out for cheaply-made room darkening Roman Shades.Christy - Room Darkening Curtains info from http://roomdarkeningcurtains.net